package test;

import java.sql.*;

public class test { // 下面定义一些全局静态参数，用于数据库连接

    static final String driver = "com.mysql.jdbc.Driver";
    static final String url = "jdbc:mysql://localhost:3306/test";
    static final String user = "root";
    static final String password = "hello";

    public static void main(String[] args) throws SQLException {

        Connection con = null; //创建一个连接对象
        Statement stmt = null; //创建一个语句对象
        ResultSet rs = null;

        try {
            Class.forName(driver);
            con = DriverManager.getConnection(url, user, password); //连接数据库
            con.setAutoCommit(false); // 关掉自动事务递交

            stmt = con.createStatement(); //初始化语句

           String query1 = "update test1 set name ='Shanghai' where id >100";
           String query2 = "update test1 set name ='Beijing' where id >50 and id <90";
           String query3 = "select * from test1 where id >50";

           stmt.executeUpdate(query1);
           stmt.executeUpdate(query2);
           rs = stmt.executeQuery(query3);

           con.commit();

            System.out.println("-----------------");
            System.out.println("执行结果如下所示:");
            System.out.println("-----------------");
            String uid = null;
            String name = null;

            while (rs.next()) {
                //获取stuname这列数据
                uid = rs.getString("id");
                //获取stuid这列数据
                name = rs.getString("name");
                //输出结果
                System.out.println(uid + "\t" + name);
            }
            rs.close(); //关语句
            con.close(); //关连接
        } catch (ClassNotFoundException e) {//如果 JDBC class 找不到捕获抛异常
            //数据库驱动类异常处理
            System.out.println("找不到数据库驱动");
            e.printStackTrace();
        } catch (SQLException e) { // JDBC 层工作中有问题抛异常
            System.err.println("无法连接到数据库");
            e.printStackTrace();
        } catch (Exception e) { // 执行操作有问题抛异常
            con.rollback(); // 失败执行事务回滚
            e.printStackTrace();
        } finally {
            System.out.println("关闭连接");
            if (con !=null) try {con.close(); } catch (SQLException ignore) {} //关闭不掉链接就抛异常
        }
    }

}