JDBC实现银行的转账事务

小鱼儿 2022-06-10 14:38 313阅读 0赞

import java.sql.*;
    
    public class TestDemo {
    
    	private static String driver = "com.mysql.jdbc.Driver";
    	private static String url = "jdbc:mysql:///test";
    	private static String user = "root";
    	private static String password = "";
    
    	/**
    	 * 连接数据库的方法
    	 */
    	public static Connection getCon() throws Exception {
    		Class.forName(driver);
    		Connection con = DriverManager.getConnection(url, user, password);
    		return con;
    	}
    
    	/**
    	 * 关闭数据库的方法
    	 */
    	public static void close(Connection con, PreparedStatement ps, ResultSet rs) throws Exception {
    		if (rs != null)
    			rs.close();
    		if (ps != null)
    			ps.close();
    		if (con != null)
    			con.close();
    	}
    
    	/**
    	 * 测试
    	 */
    	@SuppressWarnings("unused")
    	public static void main(String[] args) throws Exception {
    		Connection con = null;
    		PreparedStatement ps1 = null;
    		PreparedStatement ps2 = null;
    		String sql = "update bank set money=money-500 where userid=1";
    		String sql2 = "update bank set money=money+500 where userid=2";
    		try {
    			con = getCon();
    			con.setAutoCommit(false);
    			ps1 = con.prepareStatement(sql);
    			int result1 = ps1.executeUpdate();
    			ps2 = con.prepareStatement(sql2);
    			int result2 = ps2.executeUpdate();
    			if (false)
    				throw new RuntimeException("模拟异常");
    			if (result1 == 1 && result2 == 1) {
    				System.out.println("转账成功！");
    				con.commit();
    			} else {
    				System.out.println("转账失败,已回滚！");
    				con.rollback();
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    			con.rollback();
    			System.out.println("转账失败,已回滚！");
    		} finally {
    			close(con, ps1, null);
    			close(con, ps2, null);
    		}
    	}
    }

DROP TABLE IF EXISTS bank;
    CREATE TABLE bank (id int(11) NOT NULL, userid int(11) NOT NULL, money varchar(20) NOT NULL, PRIMARY KEY (id));
    INSERT INTO bank VALUES (1, 1, '10000'), (2, 2, '10000');