SpringBoot整合Mybatis实现增删改查的功能

Posted 2020-11-05 dzwyx521

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了SpringBoot整合Mybatis实现增删改查的功能相关的知识，希望对你有一定的参考价值。

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。

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。

[java] view plain copy

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

[html] view plain copy

#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

[html] view plain copy

<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。

[java] view plain copy

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。

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：

[sql] view plain copy

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。

[java] view plain copy

@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。

[java] view plain copy

@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：

[java] view plain copy

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);
}