使用Mybatis进行CRUD操作（测试类实现）

朴灿烈づ我的快乐病毒、 2021-11-26 08:36 340阅读 0赞

**项目主体结构：**  
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**首先我在mybatis-config.xml中定义了别名，这样就不用每次都写长长的完整路径了。**

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

**我的sql语句是从SQLyog中生成粘贴过来的。**  
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--------------------

**查询数据（根据ID查询）：**  
BlogMapper.xml

<select id="selectBlog" resultType="Blog" parameterType="int">
    		select * from blog where id = #{ id}
    	</select>

BlogMapper.java

public interface BlogMapper { 
    	Blog selectBlog(Integer id); }

BlogMapperTest.java（测试类）

@Test
    	public void testSelectBlog() { 
    
    		SqlSession session = MyBatisUtil.getSqlSession();
    
    		BlogMapper blogMapper = session.getMapper(BlogMapper.class);
    		Blog blog = blogMapper.selectBlog(2);	
    		System.out.println(blog);
    		session.close();
    	}

--------------------

**添加数据：**  
BlogMapper.xml

<insert id="insertBlog" parameterType="Blog" useGeneratedKeys="true" keyProperty="id">
    		INSERT INTO `blog`(
    	             `title`,
    	             `authorId`,
    	             `state`,
    	             `featured`,
    	             `style`
    	             )
    		VALUES (
    		        #{ title},
    		        #{ authorId},
    		        #{ state},
    		        #{ featured},
    		        #{ style}
    		        );
    	</insert>

BlogMapper.java

public interface BlogMapper {
    	int insertBlog(Blog blog);
    	}

需要在实体类添加一个无参的方法，在里面赋值（Blog.java）

public Blog() { 
    		super();
    		this.title = "天津";
    		this.authorId = 6;
    		this.state = "NO ACTIVE";
    		this.featured =false;
    		this.style = "red";
    	}

BlogMapperTest.java（测试类）

@Test
    	public void insertBlog() { 
    
    		SqlSession session = MyBatisUtil.getSqlSession();
    
    		BlogMapper blogMapper = session.getMapper(BlogMapper.class);
    		
    		Blog blog=new Blog();
    		
    		int inblog = blogMapper.insertBlog(blog);
    		
    		session.commit();//一定要有
    		session.close();
    		System.out.println(blog);
    		System.out.println("插入"+inblog+"条记录");
    	}

--------------------

**修改数据（根据ID修改）:**  
BlogMapper.xml

<update id="updateBlog" parameterType="Blog">
    	UPDATE `blog`
    		SET 
    		  `title` = #{ title},
    		  `authorId` =  #{ authorId},
    		  `state` =  #{ state},
    		  `featured` = #{ featured},
    		  `style` = #{ style}
    		WHERE `id` = #{ id}
    	</update>

BlogMapper.java

public interface BlogMapper { 
    	int updateBlog(Blog blog);
    	}

BlogMapperTest.java（测试类）

@Test
    	public void updateBlog() { 
    
    		SqlSession session = MyBatisUtil.getSqlSession();
    
    		BlogMapper blogMapper = session.getMapper(BlogMapper.class);
    		
    		//先查询，后在基础上修改
    		Blog blog=blogMapper.selectBlog(35);
    		
    		//Blog blog=new Blog();
    		blog.setId(35);
    		blog.setTitle("内蒙古");
    // blog.setAuthorId(7);
    // blog.setState("NO ACTIVE");
    // blog.setFeatured(false);
    // blog.setStyle("blue");
    		
    		int upblog = blogMapper.updateBlog(blog);
    		
    		session.commit();
    		session.close();
    		System.out.println(blog);
    		System.out.println("修改了"+upblog+"条记录");
    
    	}

--------------------

**删除数据（根据ID删除）:**  
BlogMapper.xml

<delete id="deleteBlog" parameterType="int">
    	DELETE
    	FROM `blog`
    	WHERE `id` =#{ id}
    	</delete>

BlogMapper.java

public interface BlogMapper { 
    	int deleteBlog(Integer id);
    	}

BlogMapperTest.java（测试类）

@Test
    	public void deleteBlog() { 
    		SqlSession session = MyBatisUtil.getSqlSession();
    
    		BlogMapper blogMapper = session.getMapper(BlogMapper.class);
    	
    		int deblog = blogMapper.deleteBlog(36);
    		
    		session.commit();
    		session.close();
    
    		System.out.println("删除"+deblog+"条记录");
    	}

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