MyBatis-08-動態SQL

看完以下內容接着看：https://blog.csdn.net/lgz0921/article/details/104557800

目錄結構：

pom.xml

<?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">
    <parent>
        <artifactId>mybatis-study</artifactId>
        <groupId>org.kuang</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>mybatis-08</artifactId>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>

    </dependencies>

</project>

Blog

package com.kuang.pojo;

import lombok.Data;

import java.util.Date;

@Data
public class Blog {
    private String id;
    private String title;
    private String author;
    private Date creatTime;//屬性名和字段名不一致
    private int views;
}

BlogMapper

package com.kuang.dao;

import com.kuang.pojo.Blog;

import java.util.List;
import java.util.Map;

public interface BlogMapper {
    //插入數據
    int addBlog(Blog blog);
    //查詢博客
    List<Blog> queryBlogIF(Map map);

    //查詢第1-3號記錄的博客
    List<Blog> queryBlogForeach(Map map);

    List<Blog> queryBlogChoose(Map map);

    //更新博客
    int updateBlog(Map map);

}

BlogMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.kuang.dao.BlogMapper">
    <insert id="addBlog" parameterType="Blog">
        insert into mybatis.blog (id, title, author, creat_time, views)
            values (#{id}, #{title}, #{author}, #{creatTime}, #{views});
    </insert>

    <sql id="if-title-author">
        <if test="title != null">
            and title=#{title}
        </if>
        <if test="author != null">
            and author=#{author}
        </if>
    </sql>

    <select id="queryBlogIF" parameterType="map" resultType="blog">
        select * from mybatis.blog
        <where>
            <include refid="if-title-author" />
        </where>
    </select>

    <select id="queryBlogChoose" resultType="Blog" parameterType="map">
        select * from mybatis.blog
        <where>
            <choose>
                <when test="title != null">
                    title=#{title}
                </when>

                <when test="author != null">
                    and author=#{author}
                </when>

                <otherwise>
                    and views = #{views}
                </otherwise>
            </choose>
        </where>
    </select>

    <update id="updateBlog" parameterType="map">
        update mybatis.blog
        <set>
            <if test="title != null">
                title=#{title},
            </if>
            <if test="author != null">
                author=#{author}
            </if>
        </set>
        where id=#{id}
    </update>

    <select id="queryBlogForeach" parameterType="map" resultType="Blog">
        select * from mybatis.blog
        <where>
            <foreach collection="ids" item="id" open="and (" close=")" separator="or">
                id=#{id}
            </foreach>
        </where>
    </select>

</mapper>

IDutils

package com.kuang.utils;

import org.junit.Test;

import java.util.UUID;

@SuppressWarnings("all")//抑制警告
public class IDutils {
    public static String getID(){
        return UUID.randomUUID().toString().replaceAll("-","");
    }

    @Test
    public void test(){
        System.out.println(IDutils.getID());
        System.out.println(IDutils.getID());
        System.out.println(IDutils.getID());
    }
}

MybatisUtils

package com.kuang.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;

//SqlSessionFactory -> SqlSession
public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        try {
            //獲取使用Mybatis第一步SqlSessionFactory對象
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession(true);
    }
}

db.properties

driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/mybatis?useSSL=true&usUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false&serverTimezone=UTC
username = root
password = lgz0921

mybatis-config.xml

<?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 核心配置文件 -->
<configuration>

    <!--引入外部配置文件-->
    <properties resource="db.properties" />

    <settings>
        <!--標準的日誌工廠實現-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <typeAliases>
        <package name="com.kuang.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <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 class="com.kuang.dao.BlogMapper" />
    </mappers>
</configuration>

MyTest

import com.kuang.dao.BlogMapper;
import com.kuang.pojo.Blog;
import com.kuang.utils.IDutils;
import com.kuang.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;

@SuppressWarnings("all")
public class Mytest {
    @Test
    public void addInitBlog(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);

        Blog blog = new Blog();
        blog.setId(IDutils.getID());
        blog.setTitle("Mybatis如此簡單");
        blog.setAuthor("李廣");
        blog.setCreatTime(new Date());
        blog.setViews(9999);
        mapper.addBlog(blog);

        blog.setId(IDutils.getID());
        blog.setTitle("java如此簡單");
        mapper.addBlog(blog);

        blog.setId(IDutils.getID());
        blog.setTitle("Spring如此簡單");
        mapper.addBlog(blog);

        blog.setId(IDutils.getID());
        blog.setTitle("微服務如此簡單");
        mapper.addBlog(blog);


        sqlSession.close();
    }

    @Test
    public void queryBlogIF(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);
        HashMap map = new HashMap();
       // map.put("title","java如此簡單2");
        map.put("author","李廣");
        List<Blog> blogs = mapper.queryBlogIF(map);
        for (Blog blog : blogs) {
            System.out.println(blog);
        }
        sqlSession.close();
    }

    @Test
    public void queryBlogForeach(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);
        HashMap map = new HashMap();
        ArrayList<Integer> ids = new ArrayList<Integer>();
        map.put("ids",ids);
        ids.add(1);
        ids.add(2);
        ids.add(3);
        List<Blog> blogs = mapper.queryBlogForeach(map);
        for (Blog blog : blogs) {
            System.out.println(blog);
        }
        sqlSession.close();
    }
}

Mybatis-08.iml

<?xml version="1.0" encoding="UTF-8"?>
<module type="JAVA_MODULE" version="4" />