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 

1 package com.test.dao;
2
3 import com.test.entity.Person;
4
5 import java.sql.DriverManager;
6 import java.sql.PreparedStatement;
7 import java.sql.ResultSet;
8 import java.sql.SQLException;
9
10 /**
11 * Created by wdw on 2017/9/7.
12 */
13 public class PersonDao {
14
15 private final static String DRIVER = "com.mysql.jdbc.Driver";
16 private final static String URL = "jdbc:mysql://localhost:3306/wdw";
17 private final static String USERNAME = "root";
18 private final static String PASSWORD = "123456";
19
20 /**
21 * 添加一个人
22 *
23 * @param person
24 * @return boolean
25 */
26 public boolean insert(Person person) {
27 boolean flag = false;//
28 try {
29 Class.forName(DRIVER);//加载数据库驱动
30 java.sql.Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
31 // 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
32 String sql = "INSERT INTO sys_users(id,name,code) VALUES(?,?,?)";//编写sql语句
33 PreparedStatement ps = conn.prepareStatement(sql);////创建预处理对象ps
34 ps.setInt(1, person.getId());
35 ps.setString(2, person.getName());
36 ps.setString(3, person.getCode());
37
38 if (ps.executeUpdate() > 0) {
39 flag = true;
40 }
41 System.out.print(flag);
42 ps.close();
43 conn.close();
44
45 } catch (ClassNotFoundException e) {
46
47 e.printStackTrace();
48 } catch (SQLException e) {
49 e.printStackTrace();
50 }
51 return flag;
52 }
53
54 /**
55 * 添加一个人
56 *
57 * @param id
58 * @return boolean
59 */
60 public Person selectById(String id) {
61 Person p = new Person();
62 try {
63 Class.forName(DRIVER);//加载数据库驱动
64 java.sql.Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
65 String sql = "delete sys_users where id=" + id;//编写sql语句
66 PreparedStatement ps = conn.prepareStatement(sql);////创建预处理对象ps
67 ResultSet r = ps.executeQuery();
68 while (r.next()) {
69 p.setId(r.getInt("id"));
70 p.setName((r.getString("code")));
71 p.setCode(r.getString("name"));
72 }
73
74 ps.close();
75 conn.close();
76
77 } catch (ClassNotFoundException e) {
78
79 e.printStackTrace();
80 } catch (SQLException e) {
81 e.printStackTrace();
82 }
83 return p;
84 }
85
86 }

View Code

entity：entity目录(实体)，实体就是一个特定的软件模块。

1 package com.test.entity;
2
3 /**
4 * Created by wdw on 2017/9/7.
5 */
6 public class Person {
7
8 private int id;
9 private String code;
10 private String name;
11
12 public int getId() {
13 return id;
14 }
15
16 public void setId(int id) {
17 this.id = id;
18 }
19
20 public String getCode(){
21 return this.code;
22
23 }
24 public void setCode(String code)
25 {
26 this.code=code;
27
28 }
29 public String getName(){
30 return this.name;
31
32 }
33 public void setName(String name)
34 {
35 this.name=name;
36
37 }
38 }

View Code

test：test目录，最终的试行测试。

1 package com.test.test;
2
3 import com.test.dao.PersonDao;
4 import com.test.entity.Person;
5
6 /**
7 * Created by wdw on 2017/9/7.
8 */
9 public class test {
10 public static void main(String[] args) {
11 Person ps = new Person();
12 ps.setId(1);
13 ps.setCode("编号");
14 ps.setName("张三");
15 PersonDao s = new PersonDao();
16 boolean aResult = s.insert(ps); //add a use
17 boolean uResult = s.insert(ps); //delete a use
18 boolean dResult = s.insert(ps); //delete a use
19 }
20
21 }

View Code

 

4、运行测试，记得在main断点。

 

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