SpringBoot--整合MyBatis（注解方式）

短命女 2021-08-13 21:04 600阅读 0赞

### 整合MyBatis（注解方式） ###

Users表结构

CREATE TABLE `users` (
      `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',
      `username` varchar(32) DEFAULT NULL COMMENT '用户名',
      `password` varchar(32) DEFAULT NULL COMMENT '密码',
      `sex` varchar(32) DEFAULT NULL,
      `nick_name` varchar(32) DEFAULT NULL,
      PRIMARY KEY (`id`),
      UNIQUE KEY `username` (`username`) USING HASH
    ) ENGINE=InnoDB AUTO_INCREMENT=39 DEFAULT CHARSET=utf8;

添加pom文件

<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>com.lynch.springboot</groupId>
        <artifactId>spring-boot-mybatis-annotation</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.10.RELEASE</version>
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
            
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper-spring-boot-starter</artifactId>
                <version>1.1.1</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <optional>true</optional>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    </project>

application.properties 添加相关配置

#mybatis.type-aliases-package=com.lynch.entity
    
    spring.datasource.driverClassName = com.mysql.jdbc.Driver
    spring.datasource.url = jdbc:mysql://192.168.1.149:3306/aa?useUnicode=true&characterEncoding=utf-8&useSSL=false
    spring.datasource.username = root
    spring.datasource.password = attack

springboot会自动加载spring.datasource.\*相关配置，数据源就会自动注入到sqlSessionFactory中，sqlSessionFactory会自动注入到Mapper中，对于开发人员不用管，直接拿来使用即可。

在启动类中添加对mapper包扫描@MapperScan

package com.lynch;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    @MapperScan("com.lynch.mapper")
    public class Application { 
    
        public static void main(String[] args) { 
            SpringApplication.run(Application.class, args);
        }
    }

或者直接在Mapper类上面添加注解@Mapper，建议使用上面那种，不然每个mapper加个注解也挺麻烦的。

Mapper

package com.lynch.mapper;
    
    import java.util.List;
    
    import org.apache.ibatis.annotations.Delete;
    import org.apache.ibatis.annotations.Insert;
    import org.apache.ibatis.annotations.InsertProvider;
    import org.apache.ibatis.annotations.Param;
    import org.apache.ibatis.annotations.Result;
    import org.apache.ibatis.annotations.Results;
    import org.apache.ibatis.annotations.Select;
    import org.apache.ibatis.annotations.SelectProvider;
    import org.apache.ibatis.annotations.Update;
    import org.apache.ibatis.annotations.UpdateProvider;
    
    import com.lynch.entity.UserEntity;
    import com.lynch.enums.SexEnum;
    
    public interface UserMapper { 
    
        @Select("SELECT * FROM users")
        @Results({  @Result(property = "sex", column = "sex", javaType = SexEnum.class),
                   @Result(property = "nickName", column = "nick_name") })
        List<UserEntity> getAll();
    
        @Select("SELECT * FROM users WHERE id = #{id}")
        @Results({  @Result(property = "sex", column = "sex", javaType = SexEnum.class),
                @Result(property = "nickName", column = "nick_name") })
        UserEntity getOne(Long id);
    
        @Insert("insert into users(username,password,sex) values(#{username}, #{password}, #{sex})")
        int insert(UserEntity user);
        
        @Update("UPDATE users SET userName=#{username},nick_name=#{nickName} WHERE id =#{id}")
        void update(UserEntity user);
    
        @Delete("DELETE FROM users WHERE id =#{id}")
        void delete(Long id);
        
        @InsertProvider(type=UserProvider.class, method = "batchInsert")
        int batchInsert(@Param("userList")List<UserEntity> userList);
        
        @SelectProvider(type = UserProvider.class, method = "queryUser")
        @Results({  
            @Result(property = "sex", column = "sex", javaType = SexEnum.class),
            @Result(property = "nickName", column = "nick_name") 
        })
        public List<UserEntity> queryUser(UserEntity user);
        
        @UpdateProvider(type = UserProvider.class, method = "updateUser")
        public int updateUser(@Param("U")UserEntity user);
    }

package com.lynch.mapper;
    
    import java.util.List;
    import java.util.Map;
    
    import org.apache.ibatis.annotations.Param;
    import org.apache.ibatis.jdbc.SQL;
    
    import com.github.pagehelper.util.StringUtil;
    import com.lynch.entity.UserEntity;
    
    /** * 利用@Provider实现动态SQL * * @author Lynch * */
    public class UserProvider { 
        public String queryUser(UserEntity user) { 
            StringBuffer sql = new StringBuffer("select * from users where 1=1 ");
            if(StringUtil.isNotEmpty(user.getUsername())) { 
                sql.append(String.format("and username like '%s'", "%"+user.getUsername()+"%"));
            }
            
            return sql.toString();
        }
        
        public String batchInsert(Map map) { 
            List<UserEntity> userList = (List<UserEntity>)map.get("userList");
            StringBuffer sql = new StringBuffer("insert into users (username,password) values ");
            
            for(UserEntity user : userList) { 
                sql.append(String.format("('%s', '%s'),", user.getUsername(), user.getPassword()));
            }
            
            sql = sql.deleteCharAt(sql.length() -1);
            System.out.println(sql.toString());
            return sql.toString();
        }
        
        public String updateUser(@Param("U")UserEntity user) { 
                SQL sql = new SQL(){ { 
                UPDATE("users");
                
                if (StringUtil.isNotEmpty(user.getNickName())){ 
                    SET("nick_name = #{U.nickName}");
                }
                
                WHERE("id = #{U.id}");
            }};
            
            return sql.toString();
        }
        
    
    }

**注意，使用\#符号和$符号的不同：**

// This example creates a prepared statement, something like select * from teacher where name = ?;
    @Select("Select * from teacher where name = #{name}")
    Teacher selectTeachForGivenName(@Param("name") String name);
    
    // This example creates n inlined statement, something like select * from teacher where name = 'someName';
    @Select("Select * from teacher where name = '${name}'")
    Teacher selectTeachForGivenName(@Param("name") String name);

单元测试

package com.lynch.mapper;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.junit4.SpringRunner;
    
    import com.lynch.entity.UserEntity;
    import com.lynch.enums.SexEnum;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest
    public class UserMapperTest { 
    
        @Autowired
        private UserMapper userMapper;
    
        @Test
        public void insert() throws Exception { 
            int result = 0;
            try { 
                result = userMapper.insert(new UserEntity("lisi", "123456", SexEnum.MAN));
            } catch (Exception e) { 
                System.out.println(e.getMessage().indexOf("ConstraintViolationException"));
            }
            System.out.println("result=" + result);
        }
        
        @Test
        public void batchInsert() throws Exception { 
            List<UserEntity> userList = new ArrayList<UserEntity>();
            userList.add(new UserEntity("a","a",SexEnum.MAN));
            userList.add(new UserEntity("c","b",SexEnum.MAN));
            userList.add(new UserEntity("b","b",SexEnum.WOMAN));
            
            System.out.println("result=" + userMapper.batchInsert(userList)); 
        }
    
    
        @Test
        public void getAll() throws Exception { 
            List<UserEntity> users = userMapper.getAll();
            System.out.println(users.toString());
        }
    
        @Test
        public void testUpdate() throws Exception { 
            UserEntity user = userMapper.getOne(45L);
            System.out.println(user.toString());
            user.setNickName("neo");
            user.setSex(SexEnum.WOMAN);
            userMapper.update(user);
        }
        
        @Test
        public void queryUser() throws Exception { 
            UserEntity user = new UserEntity();
            user.setUsername("l");
            System.out.println(userMapper.queryUser(user)); 
        }
        
        @Test
        public void updateUser() throws Exception { 
            UserEntity user = new UserEntity();
            user.setId(45L);
            user.setNickName("aaa");
            System.out.println(userMapper.updateUser(user)); 
        }
    
    }