数据库事务

package com.test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Savepoint;
import java.sql.Statement;

public class TestTransaction {
	
	public static void main(String[] args) throws SQLException {
		
		Connection conn = null;
		Statement stmt = null;
		Savepoint sp = null;
		try{
			Class.forName("com.mysql.jdbc.Driver");
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/for117", "root", "admin");
			conn.setAutoCommit(false);
			stmt = conn.createStatement();
			stmt.executeUpdate("update  tb_test set number = number*2 where id = 1");
			sp =  conn.setSavepoint();
			stmt.executeUpdate("update  tb_test set number = number*2 where id = 2");
			int i = 34;
			int b = i*2;
			if(b>3){
				throw new Exception();
			}
			stmt.executeUpdate("update  tb_test set number = number*2 where id = 3");
			conn.commit();
		}catch (Exception e) {
		  conn.rollback(sp);
		  conn.commit();
		}
	}
}