MySQL的批处理

批处理，降低与数据库的连接次数，提高执行效率。
BatchDemo.java文件：

package com.itheima.jdbc;import java.sql.Connection;import java.sql.Statement;import org.junit.Test;import com.itheima.util.JdbcUtil;/** * 批处理，降低与数据库的连接次数，提高执行效率 * @author wym * */public class BatchDemo {    /*     create database day16;     use day16;     create table t1(        id int primary key,        name varchar(100)     );     */    //向数据库中插入2条记录，再把第1条删掉    @Test    public void test1() throws Exception{        Connection conn = JdbcUtil.getConnection();        Statement stmt = conn.createStatement();        String sql1 = "insert into t1 values(1,'aaa')";        String sql2 = "insert into t1 values(2,'bbb')";        String sql3 = "delete from t1 where id=1";        stmt.addBatch(sql1);//Statement实例内部有一个List，sql语句加到List中了        stmt.addBatch(sql2);        stmt.addBatch(sql3);        int[] ii = stmt.executeBatch();//返回的是一个数组，数组的元素为每条语句影响到的行数        for(int i : ii){            System.out.println(i);        }        JdbcUtil.release(null, stmt, conn);    }    //插入10条记录    @Test    public void test2() throws Exception{        Connection conn = JdbcUtil.getConnection();        java.sql.PreparedStatement stmt = conn.prepareStatement("insert into t1 values(?,?)");        for(int i=0; i<10; i++){            stmt.setInt(1, i+1);            stmt.setString(2,"aaaa"+(i+1));            stmt.addBatch();        }        stmt.executeBatch();//返回的是一个数组，数组的元素为每条语句影响到的行数        JdbcUtil.release(null, stmt, conn);    }    //插入10000条数据    @Test    public void test3() throws Exception{        Connection conn = JdbcUtil.getConnection();        java.sql.PreparedStatement stmt = conn.prepareStatement("insert into t1 values(?,?)");        for(int i=0; i<10000; i++){            stmt.setInt(1, i+1);            stmt.setString(2,"aaaa"+(i+1));            stmt.addBatch();            if(i%1000 ==0){                stmt.executeBatch();                stmt.clearBatch();            }        }        stmt.executeBatch();//返回的是一个数组，数组的元素为每条语句影响到的行数        JdbcUtil.release(null, stmt, conn);    }}

JdbcUtil.java文件：

package com.itheima.util;import java.io.IOException;import java.io.InputStream;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Properties;//工具类public class JdbcUtil {    private static String driverClass;    private static String url;    private static String user;    private static String password;    static{        try {            ClassLoader cl = JdbcUtil.class.getClassLoader();            InputStream in = cl.getResourceAsStream("dbcfg.properties");            Properties props = new Properties();            props.load(in);            driverClass = props.getProperty("driverClass");            url = props.getProperty("url");            user = props.getProperty("user");            password = props.getProperty("password");            Class.forName(driverClass);        } catch (Exception e) {            throw new ExceptionInInitializerError(e);        }    }    public static Connection getConnection() throws Exception{        Connection conn = DriverManager.getConnection(url,user, password);        return conn;    }    public static void release(ResultSet rs,Statement stmt,Connection conn){        if(rs!=null){            try {                rs.close();            } catch (SQLException e) {                e.printStackTrace();            }            rs = null;        }        if(stmt!=null){            try {                stmt.close();            } catch (SQLException e) {                e.printStackTrace();            }            stmt = null;        }        if(conn!=null){            try {                conn.close();            } catch (SQLException e) {                e.printStackTrace();            }            conn = null;        }    }}

dbcnfg.properties文件：

driverClass=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/day16user=rootpassword=admin

运行结果：
1 aaaa1
2 aaaa2
3 aaaa3
4 aaaa4
5 aaaa5
。。。共10000条