数据库实验实现

import java.sql.*;

public class JDBCUtils {
	    private static String url="jdbc:mysql://localhost:3306/person";
	    private static String user="root";
	    private static String password="root";
	    private static String driver="com.mysql.jdbc.Driver";
	    /**
	     * 文件的读取，只需要读取一次即可拿到这些值。使用静态代码块
	     */
	    static{	
	            // 注册驱动
	            try {
					Class.forName(driver);
				} catch (ClassNotFoundException e) {
					e.printStackTrace();
				}   
	    }
	
	    /**
	     * 获取连接
	     * @return 连接对象
	     */
	    public static Connection getConnection() throws SQLException {
	
	        return DriverManager.getConnection(url, user, password);
	    }
	
	    /**
	     * 释放资源
	     * @param stmt
	     * @param conn
	     */
	    public static void close(Statement stmt,Connection conn){
	        if( stmt != null){
	            try {
	            	
	            	stmt.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	
	        if( conn != null){
	            try {
	                conn.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	    }
	
	    /**
	     * 释放资源
	     * @param stmt
	     * @param conn
	     */
	    public static void close(ResultSet rs,Statement stmt, Connection conn){
	        if( rs != null){
	            try {
	                rs.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	
	        if( stmt != null){
	            try {
	                stmt.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	
	        if( conn != null){
	            try {
	                conn.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	    }
	
	}

import java.sql.*;

public class Test {

    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement pstmt1 = null;
        PreparedStatement pstmt2 = null;
        PreparedStatement pstmt3 = null;
        PreparedStatement pstmt4 = null;
        try {
            //1.获取连接
            conn = JDBCUtils.getConnection();
            //开启事务
            conn.setAutoCommit(false);

            //2.定义sql
            
            String sql1 = "select *from account";
            String sql2 = "update account set balance = balance - ? where id = ?";
        
            String sql3 = "update account set balance = balance + ? where id = ?";

            //3.获取执行sql对象

            pstmt1 = conn.prepareStatement(sql2);
            pstmt2 = conn.prepareStatement(sql3);
            pstmt3 = conn.prepareStatement(sql1);

            //4. 设置参数
            pstmt1.setDouble(1,500);
            pstmt1.setInt(2,1);

            pstmt2.setDouble(1,500);
            pstmt2.setInt(2,2);
            //5.执行sql
            ResultSet resultSet = pstmt3.executeQuery();
            while(resultSet.next()){

                //获取数据
                int id = resultSet.getInt(1);
                String name = resultSet.getString("name");
                double balance = resultSet.getDouble(3);

                System.out.println(id + "---" + name + "---" + balance);
            }
            //执行更改操作
            pstmt1.executeUpdate();
            pstmt2.executeUpdate();
            ResultSet resultSet1 = pstmt3.executeQuery();
            System.out.println("改变后的结果：");
            while(resultSet1.next()){

                //获取数据
                //6.2 获取数据
                int id = resultSet1.getInt(1);
                String name = resultSet1.getString("name");
                double balance = resultSet1.getDouble(3);

                System.out.println(id + "---" + name + "---" + balance);
            }
            // 手动制造异常


            pstmt2.executeUpdate();
            //提交事务
            conn.commit();
        } catch (Exception e) {
            //事务回滚
            try {
                if(conn != null) {
                    conn.rollback();
                }
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
        }finally {
            JDBCUtils.close(pstmt1,conn);
            JDBCUtils.close(pstmt2,null);
        }
    }
}