java 连接mysql增删改查

1、创建mysql测试表 

2、按下图创建3个文件夹与3个类

3、三个类的代码

PersionDao ：目录(Data Access Object), 数据访问对象是第一个面向对象的数据库接口 

package com.test.dao;

import com.test.entity.Person;

import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * Created by wdw on 2017/9/7.
 */
public class PersonDao {

    private final static String DRIVER = "com.mysql.jdbc.Driver";
    private final static String URL = "jdbc:mysql://localhost:3306/wdw";
    private final static String USERNAME = "root";
    private final static String PASSWORD = "123456";

    /**
     * 添加一个人
     *
     * @param person
     * @return boolean
     */
    public boolean insert(Person person) {
        boolean flag = false;//
        try {
            Class.forName(DRIVER);//加载数据库驱动
            java.sql.Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
//            使用jar包中的connection接口，并通过DriveManager类的静态方法getConnection()创建连接对象conn
            String sql = "INSERT INTO sys_users(id,name,code) VALUES(?,?,?)";//编写sql语句
            PreparedStatement ps = conn.prepareStatement(sql);////创建预处理对象ps
            ps.setInt(1, person.getId());
            ps.setString(2, person.getName());
            ps.setString(3, person.getCode());

            if (ps.executeUpdate() > 0) {
                flag = true;
            }
            System.out.print(flag);
            ps.close();
            conn.close();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return flag;
    }

    /**
     * 添加一个人
     *
     * @param id
     * @return boolean
     */
    public Person selectById(String id) {
        Person p = new Person();
        try {
            Class.forName(DRIVER);//加载数据库驱动
            java.sql.Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            String sql = "delete sys_users where id=" + id;//编写sql语句
            PreparedStatement ps = conn.prepareStatement(sql);////创建预处理对象ps
            ResultSet r = ps.executeQuery();
            while (r.next()) {
                p.setId(r.getInt("id"));
                p.setName((r.getString("code")));
                p.setCode(r.getString("name"));
            }

            ps.close();
            conn.close();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return p;
    }

}

entity：entity目录(实体)，实体就是一个特定的软件模块。

package com.test.entity;

/**
 * Created by wdw on 2017/9/7.
 */
public class Person {

    private int id;
    private String code;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getCode(){
        return  this.code;

    }
    public  void  setCode(String code)
    {
        this.code=code;

    }
    public String getName(){
        return  this.name;

    }
    public  void  setName(String name)
    {
        this.name=name;

    }
}

test：test目录，最终的试行测试。

package com.test.test;

import com.test.dao.PersonDao;
import com.test.entity.Person;

/**
 * Created by wdw on 2017/9/7.
 */
public class test {
    public static void main(String[] args) {
        Person ps = new Person();
        ps.setId(1);
        ps.setCode("编号");
        ps.setName("张三");
        PersonDao s = new PersonDao();
        boolean aResult = s.insert(ps);  //add a use
        boolean uResult = s.insert(ps);  //delete a use
        boolean dResult = s.insert(ps);  //delete a use
    }

}

4、运行测试，记得在main断点。