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。