摘要：
//maven.apache.org.xsd/maven-4.0.0.xsd“>；description>；/maven-jar-plugin.version>；spring-boot-starter-web<；org.springframework.boot<；spring-boot-starter-test<；--https；
1、C3P0是一个开源的JDBC连接池，它实现了数据源和JNDI绑定，支持JDBC3规范和JDBC2的标准扩展，同时在Hibernate、Spring项目开发中被广泛应用。修改项目的pom.xml配置文件，添加C3P0依赖支持管理，由于要连接mysql，所以也要加入mysql的依赖包，如下所示：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 5 https://maven.apache.org/xsd/maven-4.0.0.xsd"> 6 7 <modelVersion>4.0.0</modelVersion> 8 <parent> 9 <!-- spring-boot-starter-parent就是官方给出的快速构建SpringBoot项目的公共父pom.xml配置文件支持。 --> 10 <groupId>org.springframework.boot</groupId> 11 <artifactId>spring-boot-starter-parent</artifactId> 12 <version>2.3.4.RELEASE</version> 13 <relativePath /> <!-- lookup parent from repository --> 14 </parent> 15 16 <groupId>com.bie</groupId> 17 <artifactId>springboot-01</artifactId> 18 <version>0.0.1-SNAPSHOT</version> 19 <name>springboot-01</name> 20 <description>Demo project for Spring Boot</description> 21 22 <properties> 23 <java.version>1.8</java.version> 24 <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version> 25 </properties> 26 27 <dependencies> 28 <dependency> 29 <groupId>org.springframework.boot</groupId> 30 <artifactId>spring-boot-starter-web</artifactId> 31 </dependency> 32 33 <dependency> 34 <groupId>org.springframework.boot</groupId> 35 <artifactId>spring-boot-starter-test</artifactId> 36 <scope>test</scope> 37 <exclusions> 38 <exclusion> 39 <groupId>org.junit.vintage</groupId> 40 <artifactId>junit-vintage-engine</artifactId> 41 </exclusion> 42 </exclusions> 43 </dependency> 44 <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 --> 45 <dependency> 46 <groupId>com.mchange</groupId> 47 <artifactId>c3p0</artifactId> 48 <version>0.9.5.2</version> 49 </dependency> 50 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> 51 <dependency> 52 <groupId>mysql</groupId> 53 <artifactId>mysql-connector-java</artifactId> 54 <!-- <version>5.1.12</version> --> 55 </dependency> 56 <dependency> 57 <groupId>org.springframework.boot</groupId> 58 <artifactId>spring-boot-configuration-processor</artifactId> 59 <optional>true</optional> 60 </dependency> 61 </dependencies> 62 63 <build> 64 <plugins> 65 <plugin> 66 <groupId>org.springframework.boot</groupId> 67 <artifactId>spring-boot-maven-plugin</artifactId> 68 </plugin> 69 </plugins> 70 </build> 71 72 </project>
然后，更新项目，Maven -> Update Project，修改application.yml配置文件，追加C3P0数据库连接池配置信息。
1 # 定义c3p0的配置，没有提示可以使用，数据库连接地址 2 c3p0.jdbcUrl=jdbc:mysql://localhost:3306/biehl?serverTimezone=UTC 3 # 数据库用户名 4 c3p0.user=root 5 # 数据库密码 6 c3p0.password=123456 7 # 数据库驱动程序 8 c3p0.driverClass=com.mysql.jdbc.Driver 9 # 最小连接数 10 c3p0.minPoolSize=2 11 # 最大连接数 12 c3p0.maxPoolSize=10 13 # 最大等待时间 14 c3p0.maxIdleTime=3000 15 # 初始化连接数 16 c3p0.initialPoolSize=3
定义c3p0的配置的时候，没有提示可以使用，数据库连接地址后面要加上?serverTimezone=UTC，不然报下面的错误，如下所示：
高版本的 spring boot搭配mysql 驱动版本较高时，如 mysql-connector-java:8.0.16，此时 driver-class-name 的值要带 cj（可不带），url 的值要带时区 serverTimezone（要带）。
1 . ____ _ __ _ _ 2 /\ / ___'_ __ _ _(_)_ __ __ _ 3 ( ( )\___ | '_ | '_| | '_ / _` | 4 \/ ___)| |_)| | | | | || (_| | ) ) ) ) 5 ' |____| .__|_| |_|_| |_\__, | / / / / 6 =========|_|==============|___/=/_/_/_/ 7 :: Spring Boot :: (v2.3.4.RELEASE) 8 9 2020-11-15 11:17:01.181 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : Starting Springboot01ApplicationTests on DESKTOP-V37QSSE with PID 4908 (started by biehl in E:eclipseeclipseworkspace_springbootspringboot-01) 10 2020-11-15 11:17:01.182 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : No active profile set, falling back to default profiles: default 11 2020-11-15 11:17:01.885 INFO 4908 --- [g-Init-Reporter] com.mchange.v2.log.MLog : MLog clients using slf4j logging. 12 2020-11-15 11:17:02.796 INFO 4908 --- [ main] com.mchange.v2.c3p0.C3P0Registry : Initializing c3p0-0.9.5.2 [built 08-December-2015 22:06:04 -0800; debug? true; trace: 10] 13 2020-11-15 11:17:03.307 INFO 4908 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' 14 2020-11-15 11:17:03.652 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : Started Springboot01ApplicationTests in 2.803 seconds (JVM running for 4.051) 15 2020-11-15 11:17:03.950 INFO 4908 --- [ main] c.m.v.c.i.AbstractPoolBackedDataSource : Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 1hgemn5ad1k0s6dw1kn7og9|3be8821f, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hgemn5ad1k0s6dw1kn7og9|3be8821f, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/biehl, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 1800000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 10, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 2, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ] 16 Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary. 17 2020-11-15 11:17:34.489 WARN 4908 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@2c34448d -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 18 19 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 20 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21] 21 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21] 22 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21] 23 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21] 24 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21] 25 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21] 26 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21] 27 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21] 28 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21] 29 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21] 30 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2] 31 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2] 32 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2] 33 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2] 34 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2] 35 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2] 36 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2] 37 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2] 38 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11] 39 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 40 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na] 41 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191] 42 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191] 43 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21] 44 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21] 45 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21] 46 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21] 47 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21] 48 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21] 49 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21] 50 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21] 51 ... 12 common frames omitted 52 53 2020-11-15 11:17:34.492 WARN 4908 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests. 54 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@bf450d2 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 55 56 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 57 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21] 58 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21] 59 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21] 60 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21] 61 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21] 62 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21] 63 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21] 64 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21] 65 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21] 66 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21] 67 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2] 68 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2] 69 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2] 70 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2] 71 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2] 72 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2] 73 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2] 74 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2] 75 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11] 76 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 77 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na] 78 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191] 79 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191] 80 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21] 81 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21] 82 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21] 83 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21] 84 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21] 85 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21] 86 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21] 87 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21] 88 ... 12 common frames omitted 89 90 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests. 91 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#1] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@6ed18a76 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 92 93 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 94 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21] 95 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21] 96 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21] 97 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21] 98 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21] 99 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21] 100 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21] 101 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21] 102 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21] 103 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21] 104 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2] 105 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2] 106 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2] 107 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2] 108 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2] 109 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2] 110 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2] 111 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2] 112 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11] 113 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 114 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na] 115 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191] 116 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191] 117 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21] 118 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21] 119 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21] 120 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21] 121 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21] 122 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21] 123 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21] 124 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21] 125 ... 12 common frames omitted 126 127 2020-11-15 11:17:34.496 WARN 4908 --- [HelperThread-#1] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests. 128 2020-11-15 11:17:34.519 INFO 4908 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
建立C3P0数据源连接池配置类，此时设置的Bean名称为dataSource。
1 package com.bie.config; 2 3 import javax.sql.DataSource; 4 5 import org.springframework.boot.context.properties.ConfigurationProperties; 6 import org.springframework.boot.jdbc.DataSourceBuilder; 7 import org.springframework.context.annotation.Bean; 8 import org.springframework.context.annotation.Configuration; 9 10 @Configuration 11 public class C3p0DatasourceConfig { 12 13 // c3p0 连接池 14 @Bean(name = "dataSource") 15 @ConfigurationProperties(prefix = "c3p0") 16 public DataSource dataSource() { 17 return DataSourceBuilder.create().type(com.mchange.v2.c3p0.ComboPooledDataSource.class).build(); 18 } 19 20 }
编写Junit测试类，测试当前DataSource配置是否正确。
1 package com.bie; 2 3 import java.sql.Connection; 4 import java.sql.PreparedStatement; 5 import java.sql.ResultSet; 6 import java.sql.SQLException; 7 8 import javax.sql.DataSource; 9 10 import org.junit.jupiter.api.Test; 11 import org.junit.runner.RunWith; 12 import org.springframework.beans.factory.annotation.Autowired; 13 import org.springframework.boot.test.context.SpringBootTest; 14 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; 15 import org.springframework.test.context.web.WebAppConfiguration; 16 17 @SpringBootTest(classes = Springboot01Application.class) // 定义要测试的Springboot类 18 @RunWith(SpringJUnit4ClassRunner.class) // 使用Junit进行测试 19 @WebAppConfiguration // 进行Web应用配置 20 class Springboot01ApplicationTests { 21 22 @Autowired 23 private DataSource dataSource; // 注入DataSource对象 24 25 @Test 26 void testConnection() throws SQLException { 27 // 获取连接 28 Connection connection = this.dataSource.getConnection(); 29 System.out.println(connection); 30 31 String sql = "select * from user_info "; 32 PreparedStatement ps = connection.prepareStatement(sql); 33 ResultSet rs = ps.executeQuery(); 34 UserInfo users = null; 35 if (rs.next()) { 36 users = new UserInfo(); 37 // 从数据库中获取值设置到实体类的setter方法中 38 users.setUserId(rs.getInt("user_id")); 39 users.setUserAccount(rs.getString("user_account")); 40 users.setUserPw(rs.getString("user_pw")); 41 users.setUserNumber(rs.getString("user_number")); 42 users.setUserName(rs.getString("user_name")); 43 users.setUserAge(rs.getInt("user_age")); 44 users.setUserSex(rs.getString("user_sex")); 45 users.setUserMark(rs.getString("user_mark")); 46 users.setIsMoney(rs.getString("is_money")); 47 System.out.println(users.toString()); 48 } 49 } 50 51 // 内部类 52 class UserInfo { 53 private Integer userId;// 用户编号 54 private String userAccount;// 用户账号 55 private String userPw;// 用户密码 56 private String userNumber;// 用户学号 57 private String userName;// 用户姓名 58 private Integer userAge;// 用户年龄 59 private String userSex;// 用户性别 60 private String userMark;// 用户标识，可以使用一张表，完成管理员和用户 61 62 private String isMoney; 63 64 public Integer getUserId() { 65 return userId; 66 } 67 68 public void setUserId(Integer userId) { 69 this.userId = userId; 70 } 71 72 public String getUserAccount() { 73 return userAccount; 74 } 75 76 public void setUserAccount(String userAccount) { 77 this.userAccount = userAccount; 78 } 79 80 public String getUserPw() { 81 return userPw; 82 } 83 84 public void setUserPw(String userPw) { 85 this.userPw = userPw; 86 } 87 88 public String getUserNumber() { 89 return userNumber; 90 } 91 92 public void setUserNumber(String userNumber) { 93 this.userNumber = userNumber; 94 } 95 96 public String getUserName() { 97 return userName; 98 } 99 100 public void setUserName(String userName) { 101 this.userName = userName; 102 } 103 104 public Integer getUserAge() { 105 return userAge; 106 } 107 108 public void setUserAge(Integer userAge) { 109 this.userAge = userAge; 110 } 111 112 public String getUserSex() { 113 return userSex; 114 } 115 116 public void setUserSex(String userSex) { 117 this.userSex = userSex; 118 } 119 120 public String getUserMark() { 121 return userMark; 122 } 123 124 public void setUserMark(String userMark) { 125 this.userMark = userMark; 126 } 127 128 public String getIsMoney() { 129 return isMoney; 130 } 131 132 public void setIsMoney(String isMoney) { 133 this.isMoney = isMoney; 134 } 135 136 @Override 137 public String toString() { 138 return "UserInfo [userId=" + userId + ", userAccount=" + userAccount + ", userPw=" + userPw 139 + ", userNumber=" + userNumber + ", userName=" + userName + ", userAge=" + userAge + ", userSex=" 140 + userSex + ", userMark=" + userMark + ", isMoney=" + isMoney + "]"; 141 } 142 143 } 144 145 }
使用该测试类的时候，如果报下面的错误，在包资源管理器中右键单击您的项目，然后build path，然后configure build path，然后libraries-->add libraries-->junit-->添加就好了。
1 java.lang.NoClassDefFoundError: org/junit/platform/launcher/core/LauncherFactory 2 at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.<init>(JUnit5TestLoader.java:31) 3 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 4 at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) 5 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) 6 at java.lang.reflect.Constructor.newInstance(Unknown Source) 7 at java.lang.Class.newInstance(Unknown Source) 8 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:367) 9 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:362) 10 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:306) 11 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:221) 12 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:205) 13 Caused by: java.lang.ClassNotFoundException: org.junit.platform.launcher.core.LauncherFactory 14 at java.net.URLClassLoader.findClass(Unknown Source) 15 at java.lang.ClassLoader.loadClass(Unknown Source) 16 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) 17 at java.lang.ClassLoader.loadClass(Unknown Source) 18 ... 11 more
2、SpringBoot整合Druid数据库连接池，Druid是阿里巴巴推出的一款数据库连接池组件（可以理解为C3P0的下一代产品），也是一个用于大数据实时查询和分析的高容错、高性能开源分布式系统，可高效处理大规模的数据并实现快速查询和分析。
修改项目的pom.xml文件，引入Druid的相关依赖库，如下所示：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 5 https://maven.apache.org/xsd/maven-4.0.0.xsd"> 6 7 <modelVersion>4.0.0</modelVersion> 8 <parent> 9 <!-- spring-boot-starter-parent就是官方给出的快速构建SpringBoot项目的公共父pom.xml配置文件支持。 --> 10 <groupId>org.springframework.boot</groupId> 11 <artifactId>spring-boot-starter-parent</artifactId> 12 <version>2.3.4.RELEASE</version> 13 <relativePath /> <!-- lookup parent from repository --> 14 </parent> 15 16 <groupId>com.bie</groupId> 17 <artifactId>springboot-01</artifactId> 18 <version>0.0.1-SNAPSHOT</version> 19 <name>springboot-01</name> 20 <description>Demo project for Spring Boot</description> 21 22 <properties> 23 <java.version>1.8</java.version> 24 <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version> 25 </properties> 26 27 <dependencies> 28 <dependency> 29 <groupId>org.springframework.boot</groupId> 30 <artifactId>spring-boot-starter-web</artifactId> 31 </dependency> 32 33 <dependency> 34 <groupId>org.springframework.boot</groupId> 35 <artifactId>spring-boot-starter-test</artifactId> 36 <scope>test</scope> 37 <exclusions> 38 <exclusion> 39 <groupId>org.junit.vintage</groupId> 40 <artifactId>junit-vintage-engine</artifactId> 41 </exclusion> 42 </exclusions> 43 </dependency> 44 <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 --> 45 <dependency> 46 <groupId>com.mchange</groupId> 47 <artifactId>c3p0</artifactId> 48 <version>0.9.5.2</version> 49 </dependency> 50 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> 51 <dependency> 52 <groupId>mysql</groupId> 53 <artifactId>mysql-connector-java</artifactId> 54 <!-- <version>5.1.12</version> --> 55 </dependency> 56 <dependency> 57 <groupId>org.springframework.boot</groupId> 58 <artifactId>spring-boot-configuration-processor</artifactId> 59 <optional>true</optional> 60 </dependency> 61 62 <!-- 引入 Druid 数据源依赖：https://mvnrepository.com/artifact/com.alibaba/druid --> 63 <dependency> 64 <groupId>com.alibaba</groupId> 65 <artifactId>druid</artifactId> 66 <version>1.1.9</version> 67 </dependency> 68 </dependencies> 69 70 <build> 71 <plugins> 72 <plugin> 73 <groupId>org.springframework.boot</groupId> 74 <artifactId>spring-boot-maven-plugin</artifactId> 75 </plugin> 76 </plugins> 77 </build> 78 79 </project>
修改application.yml配置文件，追加Druid的连接配置，如下所示：
1 # 配置当前要使用的数据源的操作类型 2 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource 3 # 配置Mysql的驱动程序类 4 spring.datasource.driver-class-name=com.mysql.jdbc.Driver 5 # 数据库连接地址 6 spring.datasource.url=jdbc:mysql://127.0.0.1:3306/biehl 7 # 数据库用户名称 8 spring.datasource.username=root 9 # 数据库密码 10 spring.datasource.password=123456 11 # 进行数据库链接池的配置，数据库最小维持连接数 12 spring.datasource.dbcp2.min-idle=1 13 # 数据库初始化提供的连接数 14 spring.datasource.dbcp2.initial-size=1 15 # 数据库最大维持连接数 16 spring.datasource.dbcp2.max-total=1 17 # 等待连接获取的最大超时时间 18 spring.datasource.dbcp2.max-wait-millis=3000
建立Druid数据源连接池配置类，此时设置的Bean名称为dataSource。也可以使用@Value手动一个一个将参数注入进来，然后设置，不过使用@ConfigurationProperties 绑定配置文件参数，此注解更加方便。
1 package com.bie.config; 2 3 import javax.sql.DataSource; 4 5 import org.springframework.boot.context.properties.ConfigurationProperties; 6 import org.springframework.context.annotation.Bean; 7 import org.springframework.context.annotation.Configuration; 8 9 import com.alibaba.druid.pool.DruidDataSource; 10 11 @Configuration 12 public class DruidDataSourceConfiguration { 13 14 /** 15 * 注入bean 16 * 17 * @return 18 */ 19 @Bean(name = "dataSource") 20 // 作用就是将全局配置文件中 前缀为 spring.datasource的属性值注入到 21 // com.alibaba.druid.pool.DruidDataSource 的同名参数中。 22 @ConfigurationProperties(prefix = "spring.datasource") 23 public DataSource dataSource() { 24 DruidDataSource datasource = new DruidDataSource(); 25 return datasource; 26 } 27 28 }
编写Junit测试类，测试当前DataSource配置是否正确。
1 package com.bie; 2 3 import java.sql.Connection; 4 import java.sql.PreparedStatement; 5 import java.sql.ResultSet; 6 import java.sql.SQLException; 7 8 import javax.sql.DataSource; 9 10 import org.junit.jupiter.api.Test; 11 import org.junit.runner.RunWith; 12 import org.springframework.beans.factory.annotation.Autowired; 13 import org.springframework.boot.test.context.SpringBootTest; 14 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; 15 import org.springframework.test.context.web.WebAppConfiguration; 16 17 @SpringBootTest(classes = Springboot01Application.class) // 定义要测试的Springboot类 18 @RunWith(SpringJUnit4ClassRunner.class) // 使用Junit进行测试 19 @WebAppConfiguration // 进行Web应用配置 20 class Springboot01ApplicationTests { 21 22 @Autowired 23 private DataSource dataSource; // 注入DataSource对象 24 25 @Test 26 void testConnection() throws SQLException { 27 // 获取连接 28 Connection connection = this.dataSource.getConnection(); 29 System.out.println(connection); 30 31 String sql = "select * from user_info "; 32 PreparedStatement ps = connection.prepareStatement(sql); 33 ResultSet rs = ps.executeQuery(); 34 UserInfo users = null; 35 if (rs.next()) { 36 users = new UserInfo(); 37 // 从数据库中获取值设置到实体类的setter方法中 38 users.setUserId(rs.getInt("user_id")); 39 users.setUserAccount(rs.getString("user_account")); 40 users.setUserPw(rs.getString("user_pw")); 41 users.setUserNumber(rs.getString("user_number")); 42 users.setUserName(rs.getString("user_name")); 43 users.setUserAge(rs.getInt("user_age")); 44 users.setUserSex(rs.getString("user_sex")); 45 users.setUserMark(rs.getString("user_mark")); 46 users.setIsMoney(rs.getString("is_money")); 47 System.out.println(users.toString()); 48 } 49 } 50 51 // 内部类 52 class UserInfo { 53 private Integer userId;// 用户编号 54 private String userAccount;// 用户账号 55 private String userPw;// 用户密码 56 private String userNumber;// 用户学号 57 private String userName;// 用户姓名 58 private Integer userAge;// 用户年龄 59 private String userSex;// 用户性别 60 private String userMark;// 用户标识，可以使用一张表，完成管理员和用户 61 62 private String isMoney; 63 64 public Integer getUserId() { 65 return userId; 66 } 67 68 public void setUserId(Integer userId) { 69 this.userId = userId; 70 } 71 72 public String getUserAccount() { 73 return userAccount; 74 } 75 76 public void setUserAccount(String userAccount) { 77 this.userAccount = userAccount; 78 } 79 80 public String getUserPw() { 81 return userPw; 82 } 83 84 public void setUserPw(String userPw) { 85 this.userPw = userPw; 86 } 87 88 public String getUserNumber() { 89 return userNumber; 90 } 91 92 public void setUserNumber(String userNumber) { 93 this.userNumber = userNumber; 94 } 95 96 public String getUserName() { 97 return userName; 98 } 99 100 public void setUserName(String userName) { 101 this.userName = userName; 102 } 103 104 public Integer getUserAge() { 105 return userAge; 106 } 107 108 public void setUserAge(Integer userAge) { 109 this.userAge = userAge; 110 } 111 112 public String getUserSex() { 113 return userSex; 114 } 115 116 public void setUserSex(String userSex) { 117 this.userSex = userSex; 118 } 119 120 public String getUserMark() { 121 return userMark; 122 } 123 124 public void setUserMark(String userMark) { 125 this.userMark = userMark; 126 } 127 128 public String getIsMoney() { 129 return isMoney; 130 } 131 132 public void setIsMoney(String isMoney) { 133 this.isMoney = isMoney; 134 } 135 136 @Override 137 public String toString() { 138 return "UserInfo [userId=" + userId + ", userAccount=" + userAccount + ", userPw=" + userPw 139 + ", userNumber=" + userNumber + ", userName=" + userName + ", userAge=" + userAge + ", userSex=" 140 + userSex + ", userMark=" + userMark + ", isMoney=" + isMoney + "]"; 141 } 142 143 } 144 145 }
如果进行连接测试使用的ORM框架的话，需要导入相应ORM框架的依赖支持包。