SpringBoot整合Mybatis实现增删改查的功能

叁歲伎倆 2022-06-07 13:09 173阅读 0赞

SpringBoot框架作为现在主流框架之一，好多框架都渐渐的移植到SpringBoot中来。前面我给大家介绍过redis，jpa等等的的整合,今天在这里给大家介绍一下Mybatis的整合过程。

想学习**分布式、微服务、JVM、多线程、架构、java、python**的童鞋，千万**不要**扫码，否则后果自负~

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SpringBoot+Mybatis一般有两种形式。一种是采用原生的xml模式，还有一种就是采用注解模式。今天我给大家介绍的就是后者，也就是注解模式。

**1.首选需要在SpringBoot的启动类里面增加用来扫描Mapper接口的注解，用来扫描Mapper包下面的接口。**

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

在这里我扫描的是项目的根目录，只要能扫描到的包含Mapper接口的范围就可以。如果大家知道Mapper接口的具体位置，建议大家可以精确一点。

**2.在application.properties配置文件中添加数据库的支持**

#DB Configuration:
    spring.datasource.driverClassName = com.mysql.jdbc.Driver
    spring.datasource.url = jdbc:mysql://localhost:3306/mybatis_db?useUnicode=true&characterEncoding=utf-8&useSSL=false
    spring.datasource.username = root
    spring.datasource.password = 220316

这个关于数据库配置的代码其实很简单

第一个是数据库所用的驱动

第二个是数据库url地址，这里我连接的名字为mybatis\_db数据库

第三第四是数据库连接的用户名和密码

**3.pom.xml文件中添加相应的jar包**

这里我就不一一介绍了，大家看一下demo就知道需要添加哪些内容了。

主要是SpringBoot相关的jar包，mybatis相关的jar包就ok了

<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/maven-v4_0_0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<groupId>springboot-mybatis</groupId>
    	<artifactId>com.joy</artifactId>
    	<packaging>war</packaging>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>com.joy Maven Webapp</name>
    	<url>http://maven.apache.org</url>
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.7.RELEASE</version>
    	</parent>
    	<properties>
    		<java.version>1.8</java.version>
    	</properties>
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>javax.servlet</groupId>
    			<artifactId>javax.servlet-api</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>com.github.pagehelper</groupId>
    			<artifactId>pagehelper</artifactId>
    			<version>4.1.0</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.mybatis.spring.boot</groupId>
    			<artifactId>mybatis-spring-boot-starter</artifactId>
    			<version>1.2.2</version>
    		</dependency>
    
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    	<build>
    		<finalName>springboot-mybatis</finalName>
    	</build>
    </project>

**4.上面准备都完成了，我们就可以开始正式mybatis项目的开发了。这里需要先新建一个数据库映射的实体类，名字叫做UserEntity。**

package com.joy.entity;
    import java.util.Date;
    public class UserEntity {
    	private long userId;
    	private String userCode;
    	private String userName;
    	private String nickName;
    	private String userPwd;
    	private Date createDate;
    	private Date updateDate;
    	public long getUserId() {
    		return userId;
    	}
    	public void setUserId(long userId) {
    		this.userId = userId;
    	}
    	public String getUserCode() {
    		return userCode;
    	}
    	public void setUserCode(String userCode) {
    		this.userCode = userCode;
    	}
    	public String getUserName() {
    		return userName;
    	}
    	public void setUserName(String userName) {
    		this.userName = userName;
    	}
    	public String getNickName() {
    		return nickName;
    	}
    	public void setNickName(String nickName) {
    		this.nickName = nickName;
    	}
    	public String getUserPwd() {
    		return userPwd;
    	}
    	public void setUserPwd(String userPwd) {
    		this.userPwd = userPwd;
    	}
    	public Date getCreateDate() {
    		return createDate;
    	}
    	public void setCreateDate(Date createDate) {
    		this.createDate = createDate;
    	}
    	public Date getUpdateDate() {
    		return updateDate;
    	}
    	public void setUpdateDate(Date updateDate) {
    		this.updateDate = updateDate;
    	}
    }

**5.因为mybatis和jpa不一样，不会通过映射实体类反向生成数据库的表和字段。所以就得我们自己来新建一个表和字段。这里我新建一个user表。**

![Center][]  
我们可以利用navicat来手动的新建这张表并加相应的数据，也可以通过sql命令来实现，sql命令如下所示：

SET FOREIGN_KEY_CHECKS=0;
    -- ----------------------------
    -- Table structure for user
    -- ----------------------------
    DROP TABLE IF EXISTS `user`;
    CREATE TABLE `user` (
      `user_id` int(10) NOT NULL AUTO_INCREMENT,
      `user_code` varchar(20) DEFAULT NULL,
      `user_name` varchar(20) DEFAULT NULL,
      `nick_name` varchar(20) DEFAULT NULL,
      `user_pwd` varchar(20) DEFAULT NULL,
      `create_date` datetime DEFAULT NULL,
      `update_date` datetime DEFAULT NULL,
      PRIMARY KEY (`user_id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
    -- ----------------------------
    -- Records of user
    -- ----------------------------
    INSERT INTO `user` VALUES ('1', '10001', 'user10001', 'no1', '123456', '2017-10-22 15:23:32', '2017-10-22 15:23:35');
    INSERT INTO `user` VALUES ('2', '10002', 'user10002', 'no2', '123456', '2017-10-22 15:23:32', '2017-10-22 15:23:35');

**6.接下来就是最重要的编写Mapper接口，我们这里采用通过注解来实现数据库的增删改查功能。**

增删改查分别对应的注解为@Insert，@Delete，@Update，@Select

关于注解的使用细节，我这里举select的例子来给大家解释一下。

@Select("select * from user")
    	@Results({
                @Result(property = "userId", column = "user_id"),
    			@Result(property = "nickName", column = "nick_name"),
    			@Result(property = "userCode", column = "user_code"), 
    			@Result(property = "userName", column = "user_name"),
    			@Result(property = "userPwd", column = "user_pwd"),
    			@Result(property = "createDate", column = "create_date"),
    			@Result(property = "updateDate", column = "update_date") })
    	public List<UserEntity> queryList();

上面是查询数据库user表的所有数据，然后会自动的转为list集合。其中column里面的字段名称必须和数据库里面表的字段一模一样，property里面的字段属性必须和UserEntity这个实体类对应的字段一模一样。

@Select("SELECT * FROM USER WHERE user_id = #{userId}")
        @Results({
                @Result(property = "userId", column = "user_id"),
                @Result(property = "nickName", column = "nick_name"),
                @Result(property = "userCode", column = "user_code"),
                @Result(property = "userName", column = "user_name"),
                @Result(property = "userPwd", column = "user_pwd"),
                @Result(property = "createDate", column = "create_date"),
                @Result(property = "updateDate", column = "update_date") })
        UserEntity findById(long userId);

上面这种形式是通过传入一个字段来查询数据。这里需要注意的是\#\{\}里面的字段内容必须和findById里面传入的字段一模一样。除了\#\{\}以外的字段都必须满足sql的查询格式。这里大家不要误解了，findById可以随便定义和jpa中是不一样的。

下面将给出增删改查的所有代码，如下所示：

package com.joy.dao;
    import java.util.List;
    import java.util.Map;
    import org.apache.ibatis.annotations.*;
    import com.joy.entity.UserEntity;
    public interface UserMapper {
    	@Select("select * from user")
    	@Results({
                @Result(property = "userId", column = "user_id"),
    			@Result(property = "nickName", column = "nick_name"),
    			@Result(property = "userCode", column = "user_code"), 
    			@Result(property = "userName", column = "user_name"),
    			@Result(property = "userPwd", column = "user_pwd"),
    			@Result(property = "createDate", column = "create_date"),
    			@Result(property = "updateDate", column = "update_date") })
    	public List<UserEntity> queryList();
        @Select("SELECT * FROM USER WHERE user_id = #{userId}")
        @Results({
                @Result(property = "userId", column = "user_id"),
                @Result(property = "nickName", column = "nick_name"),
                @Result(property = "userCode", column = "user_code"),
                @Result(property = "userName", column = "user_name"),
                @Result(property = "userPwd", column = "user_pwd"),
                @Result(property = "createDate", column = "create_date"),
                @Result(property = "updateDate", column = "update_date") })
        UserEntity findById(long userId);
    
        @Insert("INSERT INTO USER(nick_name, user_code) VALUES(#{nickName}, #{userCode})")
        int insertParam(@Param("nickName") String nickName, @Param("userCode") String userCode);
    
        @Insert("INSERT INTO USER(nick_name, user_code) VALUES(#{nickName,jdbcType=VARCHAR}, #{userCode,jdbcType=INTEGER})")
        int insertByMap(Map<String, Object> map);
    
        @Insert("insert into user(nick_name,user_code,user_name,user_pwd,create_date,update_date) values(#{nickName},#{userCode},#{userName},#{userPwd},#{createDate},#{updateDate})")
    	public int insertEntity(UserEntity entity);
    
        @Update("UPDATE user SET nick_name=#{nickName} WHERE user_id=#{userId}")
        int updateEntity(UserEntity user);
    
        @Delete("DELETE FROM user WHERE user_id =#{userId}")
        int delete(Long userId);
    
        @Delete("DELETE FROM user WHERE user_id =#{userId}")
        int deleteEntity(UserEntity entity);
    }

**7.最后就是编写相应的service和controller类来调用这些增删改查的接口。**

service类信息：

package com.joy.service;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import com.joy.dao.UserMapper;
    import com.joy.entity.UserEntity;
    @Service
    public class UserService {
    	@Autowired(required = false)
    	private UserMapper mapper;
    	
    	public List<UserEntity> queryList(){
    		List<UserEntity> userList=mapper.queryList();
    		return userList;
    	}
    
        public UserEntity findById(long userId){
            System.out.println("userId:"+userId);
            return mapper.findById(userId);
        }
    
    	public int insertEntity() {
    		UserEntity entity=new UserEntity();
    		entity.setUserName("lisi");
    		entity.setUserCode("lisi"+new Date());
    		entity.setNickName("郭靖");
    		entity.setUserPwd("123");
    		entity.setCreateDate(new Date());
    		entity.setUpdateDate(new Date());
            return mapper.insertEntity(entity);
    	}
    
        public int insertParam() {
            return mapper.insertParam("linzhiqiang","lzq");
        }
    
        public int insertByMap() {
            Map<String, Object> map=new HashMap<String, Object>();
            map.put("nickName","zhaotong");
            map.put("userCode","zt");
            return mapper.insertByMap(map);
        }
    
        public int updateEntity() {
            UserEntity entity=new UserEntity();
            entity.setUserId(1);
            entity.setNickName("郭靖");
            return mapper.updateEntity(entity);
        }
    
        public int deleteEntity() {
            UserEntity entity=new UserEntity();
            entity.setUserId(11);
            return mapper.deleteEntity(entity);
        }
    }

controller类信息：

package com.joy.controller;
    import java.util.List;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.github.pagehelper.PageHelper;
    import com.joy.entity.UserEntity;
    import com.joy.service.UserService;
    @RestController
    public class UserController {
    	@Autowired
    	private UserService userService;
    	@RequestMapping("/userlist")
    	public List<UserEntity> queryList(){
    		PageHelper.startPage(1, 2);
    		return userService.queryList();
    	}
    
        @RequestMapping("/queryUser")
        public UserEntity queryUserEntity(long userId){
            UserEntity userEntity=userService.findById(userId);
            return userEntity;
        }
    
        @RequestMapping("/insert")
    	public int insertEntity() {
            return userService.insertEntity();
    	}
    
        @RequestMapping("/insertParam")
        public int insertParam() {
            return userService.insertParam();
        }
    
        @RequestMapping("/insertByMap")
        public int insertByMap() {
            return userService.insertByMap();
        }
    
        @RequestMapping("/updateEntity")
        public int updateEntity() {
            return userService.updateEntity();
        }
    
        @RequestMapping("/deleteEntity")
        public int deleteEntity() {
            return userService.deleteEntity();
        }
    }

**8.执行结果如下所示：**  
![Center 1][]

**8.如果想要将执行的sql打印在控制台上面，可以在application.properties添加如下的配置信息。**

**logging.level.com.joy**=**DEBUG**

这里需要特别注意的是：level后面是你项目包的地址不要写的和我一样。**到这里关于SpringBoot整合Mybatis项目就介绍完毕，如果大家想要源代码的话可以去我的GitHub地址下载。**

**GitHub地址：[https://github.com/1913045515/MyBatis.git][https_github.com_1913045515_MyBatis.git]**

**如果按照博客上面写的步骤操作还有问题，可以观看我为大家录制的视频讲解。因为本人不是专业的讲师，所以可能讲的不是特别细致。有什么建议都可以提出来，谢谢大家。****视频地址：https://pan.baidu.com/s/1qYcFDow**[点击打开链接][Link 1]

**如果大家对文章有什么问题或者疑意之类的，可以加我订阅号在上面留言，订阅号上面我会定期更新最新博客。如果嫌麻烦可以直接加我wechat：lzqcode**

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[Center]: /images/20220607/953adf719e3046cb86614295ca731ff2.png
[Center 1]: /images/20220607/f66d4f5b26284d90bb8226900fcbe3b0.png
[https_github.com_1913045515_MyBatis.git]: https://github.com/1913045515/MyBatis.git
[Link 1]: https://pan.baidu.com/s/1qYcFDow
[284_method_get-resource_shareToken_6CEF0002846344EAA8E81FC9E51F5C29_entryId_182345157]: https://note.youdao.com/yws/api/group/67516516/noteresource/C5C7035B3E5147589191CE5096EC74CE/version/284?method=get-resource&shareToken=6CEF0002846344EAA8E81FC9E51F5C29&entryId=182345157