JDBC transaction

  transaction processing   jdbc

today to learn JDBC transaction processing , I do not set auto-commit and rollback when wrong, but why will still be executed after running the update operation does no wrong
direct look at the code it

import java.sql.DriverManager;
  import java.sql.Connection;
  import java.sql.Statement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  public class BatchDemo01{
  	// 定义MySQL的数据库驱动程序
  	public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;
  	// 定义MySQL数据库的连接地址
  	public static final String DBURL = "jdbc:mysql://localhost:3306/winestore" ;
  	// MySQL数据库的连接用户名
  	public static final String DBUSER = "root" ;
  	// MySQL数据库的连接密码
  	public static final String DBPASS = "root" ;
  
  	public static void main(String[] args) throws Exception{
  		Connection conn=null;
  		Statement st=null;
  		ResultSet rs=null;
  		Class.forName(DBDRIVER);
  		conn=DriverManager.getConnection(DBURL,DBUSER,DBPASS);
  		
  		conn.setAutoCommit(false);//取消自动提交
  		
  		st=conn.createStatement();
  		try{
  			st.addBatch("insert into users(user_name,password) values('剑南春','jiannanchun')");
  			st.addBatch("insert into users(user_name,password) values('口子窖','kouzijiao')");
  //下面的sql语句中我把user_name错误的写成username,
  			st.addBatch("insert into users(username,password) values('茅台','maotai')");
  			st.addBatch("insert into users(user_name,password) values('汾酒','fenjiu')");
  			int[] len=st.executeBatch();
  			System.out.println("更新了"+len.length+"条数据");
  			conn.commit();//提交事务
  		}catch(Exception e){
  			conn.rollback();//如果出错，则回滚
  		}
  		conn.close();//关闭连接
  	}
  }

When I perform discovery : In addition to the wrong piece of SQL is not executed , and the rest were executed. Is my understanding wrong? Members seeking doubts
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landlord 's code did not problem , you check under your mysql driver, and you use mysql database engine (preferably using innoDB engine ) .
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st not closed ah ,
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should be something you have a problem
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seemingly is not closed java st try to learn something in a long time had not What might have cleared
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Oh, shut up or useless
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  //判断数据库是否支持事务处理
  			DatabaseMetaData md=conn.getMetaData();
  			if(md.supportsTransactions()){
  				System.out.println("数据库支持事务处理");
  			}
  

I was judging my Mysql database supports transaction processing , the results display support
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/ / determine whether to support transaction processing database
DatabaseMetaData md = conn.getMetaData ();
if (md.supportsTransactions ()) {
System.out.println (" database supports transaction processing " ) ;
}
I was judging my Mysql database supports transaction processing , the results display support
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landlord that these whether the data is rolled back ?
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that the landlord whether these data are rolled back ?  

I just open my database , checked the users table , discovery engine using MyIsam ..........
get it , thank you