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mybatis-operate-fangneng

2021-04-14 23:36:29 作者：互联网

文件目录:

导入包：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>org.example</groupId>
<artifactId>mybatis-operate-fangneng</artifactId>
<version>1.0-SNAPSHOT</version>

<dependencies>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.23</version>
</dependency>


<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.6</version>
</dependency>

<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.3.0-alpha5</version>
<scope>test</scope>
</dependency>
</dependencies>

</project>
新建数据库：

UserDao文件：

public interface UserDao {
User selectUserById(Integer id);
/**
* 查询所有用户信息
*
* @return
*/
List<User> selectUserList();
/**
* 新增用户信息
*
* @param user
* @return
*/
int insertUser(User user);
/**
* 修改用户信息
*
* @param user
* @return
*/
int updateUserById(User user);
/**
* 删除用户信息
*
* @param id
* @return
*/
int deleteUserById(Integer id);

}
User文件：

public class User {
private Integer id;

public Integer getId() {
return id;
}

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

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public Integer getAge() {
return age;
}

public void setAge(Integer age) {
this.age = age;
}

public Integer getScore() {
return score;
}

public void setScore(Integer score) {
this.score = score;
}

private String username;
private Integer age;

@Override
public String toString() {
return "entity.User{" +
"id=" + id +
", username='" + username + '\'' +
", age=" + age +
", score=" + score +
'}';
}

private Integer score;
}
UserDao.xml文件：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="Dao.UserDao">
<select id="selectUserById" resultType="entity.User">
SELECT * FROM user WHERE id = #{id}
</select>

<select id="selectUserList" resultType="entity.User">
SELECT * FROM user
</select>

<insert id="insertUser" parameterType="entity.User">
INSERT INTO user VALUES (#{id},#{username},#{age},#{score})
</insert>
<update id="updateUserById">
UPDATE user SET
age = #{age},
username = #{username},
score = #{score}
WHERE id = #{id}
</update>

<delete id="deleteUserById">
DELETE FROM user WHERE id = #{id}
</delete>
</mapper>
mybatis-config.xml文件：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

<environments default="development">
<environment id="development">

<transactionManager type="JDBC"/>

<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis_demo?useSSL=false"/>
<property name="username" value="root"/>
<property name="password" value="1003"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper class="Dao.UserDao"/>
</mappers>
</configuration>
UserTest文件：

@SuppressWarnings({"Duplicates"})
public class UserTest {
public static void main(String[] args) throws IOException, SQLException {
// 读取配置文件
InputStream configuration = Resources.getResourceAsStream("mybatis-config.xml");
// 得到 SqlSessionFactory 核心类
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
// 开始一个 sql 会话
SqlSession session = sqlSessionFactory.openSession();
// 得到 mapper
UserDao mapper = session.getMapper(UserDao.class);
// 调用通过用户id查询用户信息的方法
User user = mapper.selectUserById(1);
System.out.println(user);
// 调用查询所有用户信息的方法
List<User> userList = mapper.selectUserList();
for(int i=1;i<userList.size();i++){
System.out.println(userList.get(i));
}
// 调用查询所有用户信息的方法
/*List<User> userListBefore = mapper.selectUserList();
for(int i=1;i<userList.size();i++){
System.out.println(userList.get(i));
}*/
// 创建一个要新增的对象并赋值
User insertUser = new User();
insertUser.setId(6);
insertUser.setUsername("anne");
insertUser.setAge(18);
insertUser.setScore(600);
// 调用新增用户信息的方法
/* int count = mapper.insertUser(insertUser);*/
// 调用查询所有用户信息的方法
/*List<User> userListAfter = mapper.selectUserList();
for(int i=1;i<userList.size();i++){
System.out.println(userList.get(i));
}*/
// 调用通过用户id查询用户信息的方法
User userBefore = mapper.selectUserById(6);
System.out.println(userBefore);
/* // 把成绩改为900
userBefore.setScore(900);
// 调用修改用户信息的方法
mapper.updateUserById(userBefore);*/
// 调用通过用户id查询用户信息的方法
User userAfter = mapper.selectUserById(6);
System.out.println(userAfter);
// 调用查询所有用户信息的方法
List<User> userListBefore = mapper.selectUserList();
for(int i=1;i<userList.size();i++){
System.out.println(userList.get(i));
}
// 调用删除用户信息的方法
int count = mapper.deleteUserById(6);
// 调用查询所有用户信息的方法
List<User> userListAfter = mapper.selectUserList();
for(int i=1;i<userList.size();i++){
System.out.println(userList.get(i));
}
// 提交session
session.commit();
// 关闭会话
session.close();
}
}
提示：数据库新增和删除修改只能运行一次，再次运行将报错

标签：mapper,fangneng,public,User,mybatis,Integer,operate,id,user
来源： https://www.cnblogs.com/pangfeng/p/14660463.html