文章目錄

1.主題思路

mybatis的使用
1.創建工程
2.導入jar包
3.創建核心配置文件
常用的參數：重點
configuration配置核心的文件
properties屬性，導入配置文件
setting常用設置
typeAliases起別名
enviroment環境配置
mappers映射器
4.創建實體類
5.創建接口
6.創建Mapper映射文件
7.抽取mybatis的工具類
8.創建測試類

2.前提準備

創建數據庫表

use day04_db;
create table user (
  id int primary key auto_increment,
  username varchar(20) not null,
  birthday date,
  sex char(1) default '男',
  address varchar(50)
);

insert into user values (null, '孫悟空','1980-10-24','男','花果山水簾洞');
insert into user values (null, '白骨精','1992-11-12','女','白虎嶺白骨洞');
insert into user values (null, '豬八戒','1983-05-20','男','福臨山雲棧洞');
insert into user values (null, '蜘蛛精','1995-03-22','女','盤絲洞');

select * from user;

3.創建項目導包

4.創建核心配置文件

jdbc.properties文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost/day04_db
username=root
password=root

mybatis的核心配置文件

<?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">
        //以上的爲約束文件
<configuration>
    <properties resource="jdbc.properties"></properties>
    <typeAliases>
        <typeAlias type="cn.itcast.domain.User" alias="User"/>
        <typeAlias type="cn.itcast.dao.UserMapper" alias="UserMapper"/>

    </typeAliases>
    <typeHandlers></typeHandlers>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="UserMapper.xml"/>
    </mappers>
</configuration>

configuration：核心的配置，其他的配置都在其內部
properties：引入外部文件，這裏引入了jdbc.properties文件
typeAliases起別名，爲了讓很長的路徑名有個簡單的名字
environments default="development"環境配置
default爲默認加載的環境配置
其內部有四大配置
mapper存放映射文件，或者說加載配置文件

5.創建實體類

成員變量名與數據庫列名保持一致
不一致也可以，一直比較方便


package cn.itcast.domain;

import java.util.Date;

public class User {
    private  Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public User() {
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    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 Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

6.創建接口


package cn.itcast.dao;

import cn.itcast.domain.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface UserMapper {
    List<User> findAllUsers();
    User findUserById(Integer id);

    int addUser(User user);

    int updateUserById(User user);

    int deleteUserById(Integer id);

    User findUserByNameAndId(@Param("id") Integer id, @Param("username") String username);



}

7.創建對應的mapper文件

這裏創建的mapper文件爲User Mapper.xml

<?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="cn.itcast.dao.UserMapper">
    <select id="findAllUsers" resultType="User">
        select * from user
    </select>
    <select id="findUserById" resultType="User" parameterType="int">
        select * from user where id=#{id}
    </select>


    <insert id="addUser" parameterType="User">
        insert into user values(null,#{username},#{birthday},#{sex},#{address})
    </insert>


    <update id="updateUserById" parameterType="User">
        update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}
    </update>
    <delete id="deleteUserById" parameterType="int">
        delete from user where id=#{id}
    </delete>
    <select id="findUserByNameAndId"  resultType="User">
        select * from user where id=#{id} and username=#{username}
    </select>
</mapper>

8.創建日誌記錄文件


log4j.rootLogger=debug, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.SimpleLayout

創建測試類


package cn.itcast.test;
import cn.itcast.dao.UserMapper;
import cn.itcast.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.Test;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
public class UserMapperTest {
    @Test
    public void test01() throws Exception {
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> allUsers = mapper.findAllUsers();
        for (User allUser : allUsers) {
            System.out.println(allUser);
        }
    }
    @Test
    public void test02() throws Exception {
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User userById = mapper.findUserById(1);
        System.out.println(userById);
    }
    @Test
    public void test03() throws Exception {
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);
        SqlSession sqlSession = build.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setId(null);
        user.setUsername("唐昊");
        user.setBirthday(new Date());
        user.setSex("男");
        user.setAddress("斗羅大陸");
        int i = mapper.addUser(user);
        if (i == 1) {
            System.out.println("數據添加成功");
        } else {
            System.out.println("數據添加失敗");
        }
    }
    @Test
    public void test04() throws Exception {
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);
        SqlSession sqlSession = build.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setId(15);
        user.setUsername("昊天大錘");
        user.setBirthday(new Date());
        user.setSex("男");
        user.setAddress("殺戮之都");
        int i = mapper.updateUserById(user);
        if (i == 1) {
            System.out.println("更新成功");
        } else {
            System.out.println("更新失敗");
        }
    }

    @Test
    public void test05() throws Exception {
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);
        SqlSession sqlSession = build.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        int i = mapper.deleteUserById(15);
        if (i == 1) {
            System.out.println("刪除成功");

        } else {
            System.out.println("刪除失敗");
        }

    }




}

9.抽取成相應的mybatis工具類


package cn.itcast.utils;

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 java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;


public class MybatisUtils {
    private static SqlSessionFactory build = null;
    static {
        try {
            SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
            InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-cnfig.xml");
            build = sqlSessionFactoryBuilder.build(resourceAsStream);


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

    }


    public static SqlSession getSqlSession() {
        SqlSession sqlSession = build.openSession(true);
        return sqlSession;
    }



}

10.抽取成工具類之後的測試


package cn.itcast.test;

import cn.itcast.dao.UserMapper;
import cn.itcast.domain.User;
import cn.itcast.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.Date;
import java.util.List;

public class UserMapperTest02 {
    @Test
    public void test01() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> allUsers = mapper.findAllUsers();
        for (User allUser : allUsers) {
            System.out.println(allUser);
        }
    }
    @Test
    public void test02() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User userById = mapper.findUserById(1);
        System.out.println(userById);

    }
    @Test
    public void test03() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setId(null);
        user.setUsername("小舞");
        user.setBirthday(new Date());
        user.setSex("女");
        user.setAddress("錘子上");
        int i = mapper.addUser(user);
        if (i == 1) {
            System.out.println("數據添加成功");
        }

    }

    @Test
    public void test04() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setId(16);
        user.setUsername("小舞");
        user.setBirthday(new Date());
        user.setSex("女");
        user.setAddress("星斗大森林");
        int i = mapper.updateUserById(user);
        if (i == 1) {
            System.out.println("數據修改成功");
        }
    }
    @Test
    public void test05() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        int i = mapper.deleteUserById(9);
        if (i == 1) {
            System.out.println("數據刪除成功");
        }
    }
    @Test
    public void test06() throws Exception {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.findUserByNameAndId(16, "小舞");
        System.out.println(user);

    }



}

11.注意事項：

MySQL的事務提交是自動提交，mybatis的事務提交爲手動提交，需要將Session中填寫true
SqlSession sqlSession = sqlSessionFactory.openSession(true);

如果同時傳多個參數會報錯，這時需要使用
@Param（“名字”）
這個可以解決多個屬性查找的報錯問題
例如：
User findUserByNameAndId(@Param(“id”) Integer id, @Param(“username”) String username);

Mybatis的使用和核心配置

文章目錄

1.主題思路

2.前提準備

3.創建項目導包

4.創建核心配置文件

5.創建實體類

6.創建接口

7.創建對應的mapper文件

8.創建日誌記錄文件

創建測試類

9.抽取成相應的mybatis工具類

10.抽取成工具類之後的測試

11.注意事項：

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https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

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