package com.db;

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

public class ConnectionManager {
	private static Connection connection;
	public static Connection getConnection() throws ClassNotFoundException, SQLException{
		Class.forName("com.mysql.jdbc.Driver");//加载驱动类
		connection=DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root");
		return connection;
	}
}

package com.test;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import com.db.ConnectionManager;
/**
 * JDBC设置事务隔离级别
 * @author 守望幸福
 *
 */
public class UnAutoCommit {
	static Connection con;
	public static void main(String[] args) throws SQLException {
		try {
			con=ConnectionManager.getConnection();
			con.setAutoCommit(false);//connection默认自动提交事务，false为不自动提交
			DatabaseMetaData dm=con.getMetaData();
			System.out.println("是否支持事务隔离"+dm.supportsTransactions());
			System.out.println("支持事务隔离0"+dm.supportsTransactionIsolationLevel(Connection.TRANSACTION_NONE));
			System.out.println("支持事务隔离1"+dm.supportsTransactionIsolationLevel(Connection.TRANSACTION_READ_UNCOMMITTED));
			System.out.println("支持事务隔离2"+dm.supportsTransactionIsolationLevel(Connection.TRANSACTION_READ_COMMITTED));
			System.out.println("支持事务隔离4"+dm.supportsTransactionIsolationLevel(Connection.TRANSACTION_REPEATABLE_READ));
			System.out.println("支持事务隔离8"+dm.supportsTransactionIsolationLevel(Connection.TRANSACTION_SERIALIZABLE));
			con.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);//设置事务隔离级别
			Statement stmt=con.createStatement();
			int row=stmt.executeUpdate("insert into student(name,score,subject)values('李四',20,'数学')");
			System.out.println("事务提交前row："+row);
			con.commit();
			System.out.println("事务提交后row："+row);
		} catch (Exception e) {
			con.rollback();
		}
	}

}

package com.test;

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

import com.db.ConnectionManager;
/**
 * SavePoint JDBC3之后引入的新特性
 * SavePoint 接口允许用户将事务分割为多个阶段， 用户可以指定回滚事务到特定保存点，并不会回滚到事务的起点
 * @author 守望幸福
 *
 */
public class SavePoint {
	static Connection con;
	public static void main(String[] args) throws ClassNotFoundException, SQLException {
		con=ConnectionManager.getConnection();
		con.setAutoCommit(false);//connection默认自动提交事务，false为不自动提交
		con.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
		Statement stmt=con.createStatement();
		int row=stmt.executeUpdate("insert into student(name,score,subject)values('李四',20,'数学')");
		Savepoint savepoint=con.setSavepoint("first savePoint");//设置保存点
		int row1=stmt.executeUpdate("insert into student(name,score,subject)values('王五',80,'哲学')");
		con.rollback(savepoint);//回滚至保存点，在保存点之前的事务依旧提交数据持久化到数据库中，保存点之后的事务回滚，数据不会持久化
		con.commit();
		System.out.println("row："+row);
		System.out.println("row1："+row1);
	}

}