摘要：
try{fileInputStream=newFileInputStream（img）；4importjava.io.fileInputStream；28try{29fileInputStream＝newFileInputStream（img））；4243preparedStatement=connection.prepareStatement（sql）；
在mysql里面用来存储图片有一个特殊的数据对象叫做 Blob(Binary Large Object).
数据库里面插入一张图片:
第一步:需要为图片创建一个文件对象
File img = new File(proppath); FileInputStream fileInputStream = null; try { fileInputStream = new FileInputStream(img); } catch (FileNotFoundException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }
第二部：创建二进制的数据流
preparedStatement.setBinaryStream(1, fileInputStream, (int) img.length()); preparedStatement.executeUpdate();
调用的是prepared statement的setBinaryStream对象:几个参数分别是需要绑定的参数索引位置，一个文件输入流，图片的字节数
1 package core; 2 3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileNotFoundException; 6 import java.sql.Connection; 7 import java.sql.DriverManager; 8 import java.sql.PreparedStatement; 9 import java.sql.SQLException; 10 import java.sql.Statement; 11 import java.sql.ResultSet; 12 13 public class MethodReferencesTest { 14 15 public static void main(String[] args) throws CloneNotSupportedException { 16 // TODO Auto-generated method stub 17 18 Connection connection = null; 19 Statement statement = null; 20 ResultSet resultSet = null; 21 PreparedStatement preparedStatement = null; 22 String proppath = System.getProperty("user.dir") 23 + "/src/core/c9c15f0edd07ee240f3af06de6775888.jpg"; 24 25 //创建image object 26 File img = new File(proppath); 27 FileInputStream fileInputStream = null; 28 try { 29 fileInputStream = new FileInputStream(img); 30 } catch (FileNotFoundException e1) { 31 // TODO Auto-generated catch block 32 e1.printStackTrace(); 33 } 34 String sqlurl = "jdbc:mysql://172.20.23.75:3306/testdb"; 35 String sqluser = "root"; 36 String sqlpassword = "123456"; 37 String sql = "INSERT INTO Images(Data) VALUES(?)"; 38 39 try { 40 connection = DriverManager.getConnection(sqlurl, sqluser, 41 sqlpassword); 42 43 preparedStatement = connection.prepareStatement(sql); 44 preparedStatement.setBinaryStream(1, fileInputStream, 45 (int) img.length()); 46 preparedStatement.executeUpdate(); 47 48 } catch (SQLException e) { 49 // TODO Auto-generated catch block 50 e.printStackTrace(); 51 } finally { 52 try { 53 if (resultSet != null) { 54 resultSet.close(); 55 } 56 if (statement != null) { 57 statement.close(); 58 } 59 if (preparedStatement != null) { 60 preparedStatement.close(); 61 } 62 if (connection != null) { 63 connection.close(); 64 } 65 } catch (SQLException e) { 66 e.printStackTrace(); 67 } 68 } 69 70 } 71 72 }
从数据库里面读取图片
第一步:创建一个输出流对象
//创建image object File img = new File(proppath); FileOutputStream fileputStream = null; try { fileputStream = new FileOutputStream(img); } catch (FileNotFoundException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }
第二步:调用getblob()获取图片数据
1 connection = DriverManager.getConnection(sqlurl, sqluser, 2 sqlpassword); 3 4 preparedStatement = connection.prepareStatement(sql); 5 resultSet = preparedStatement.executeQuery(); 6 if (resultSet.next()) { 7 // 获取图片数据 8 Blob blob = resultSet.getBlob("Data"); 9 // 获取字节数 10 int len = (int) blob.length(); 11 byte[] buf = blob.getBytes(1, len); 12 try { 13 fileputStream.write(buf, 0, len); 14 } catch (IOException e) { 15 // TODO Auto-generated catch block 16 e.printStackTrace(); 17 } 18 19 }