mybatis學習小結——使用註解的方式實現crud

1,新建一個maven項目

2，配置pom.xml,導入相關包

​
<dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.6</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

​

3，在源碼的根目錄或者resource目錄下新建mybatis-config.xml文件，配置數據庫源，此文件爲mybatis的主配置文件

​
​
<?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.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <package name="com.sohu.zzy.dao"></package>
    </mappers>
</configuration>

​

​

4，創建實體類User，對應的在數據庫中應有相應的user表

5，創建接口類，採用註解的方式訪問數據庫

package com.sohu.zzy.dao;

import com.sohu.zzy.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

/**
 * Created by zhuzhengyi on 2019/6/11.
 */
public interface UserDao {
    /**
     * 查詢所有用戶
     * @return
     */
    @Select("select * from user")
    public List<User> findAll();

    /**
     * add user
     * @param user
     */
    @Insert("insert into user (id,name,password,age,source) values"+
            "(#{id},#{name},#{password},#{age},#{source})")
    public void saveUser(User user);

    /**
     * update user
     * @param user
     */
    @Update("update user set name=#{name}," +
            "password=#{password}," +
            "age=#{age}," +
            "source=#{source} " +
            "where id=#{id}")
    public void updateUser(User user);

    /**
     * delete user by id
     * @param id
     */
    @Delete("delete from user where id=#{id}")
    public void deleteById(int id);
}

6.創建測試用例

package com.sohu.zzy.test;

import com.sohu.zzy.dao.UserDao;
import com.sohu.zzy.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;

import java.util.List;

/**
 * Created by zhuzhengyi on 2019/6/11.
 */
public class UserTest {
    //provide globel sqlsessionfactory
    private SqlSessionFactory sqlSessionFactory;

    @Before
    public void init(){
        try {
            //get config file stream
            InputStream ins = Resources.getResourceAsStream("SqlMapConfig.xml");
            //create sqlsessionfactory object
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(ins);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * test findall
     */
    @Test
    public void findAll(){
        //create sqlsession object access sqlsessionfactory
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //get interface object by sqlsession
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        //run method in proxy object
        List<User> list = userDao.findAll();
        for(User user : list){
            System.out.println(user.getName());
        }
    }

    @Test
    public void saveUser(){
        //create sqlsession object access sqlsessionfactory
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //get interface object by sqlsession
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        User user = new User();
        user.setId(2);
        user.setName("xxxx");
        user.setPassword("asdfadf");
        user.setAge(23);
        user.setSource(2);

        userDao.saveUser(user);
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void updateUser(){
        //create sqlsession object access sqlsessionfactory
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //get interface object by sqlsession
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        User user = new User();
        user.setId(2);
        user.setName("xyyy");
        user.setPassword("asdfadf");
        user.setAge(23);
        user.setSource(2);

        userDao.updateUser(user);
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void deleteUser(){
        //create sqlsession object access sqlsessionfactory
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //get interface object by sqlsession
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        userDao.deleteById(2);
        sqlSession.commit();
        sqlSession.close();
    }

}