SpringBoot MyBatis簡單快速入門例子
MyBatis 是一款優秀的持久層框架,它支持自定義 SQL、存儲過程以及高級映射。MyBatis 免除了幾乎所有的 JDBC 代碼以及設置參數和獲取結果集的工作。MyBatis 可以通過簡單的 XML 或注解來配置和映射原始類型、接口和 Java POJO(Plain Old Java Objects,普通老式 Java 對象)為數據庫中的記錄。
二、MyBatis使用步驟1、MyBatis工程總體目錄結構
2、創建簡單的SpringBoot工程
3、添加MyBatis依賴
<!--MyBatis--><dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.32</version></dependency><dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.6</version></dependency>
4、在數據庫創建USER表
CREATE TABLE `user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(20) NOT NULL DEFAULT ’’ COMMENT ’用戶名’, `password` varchar(50) NOT NULL DEFAULT ’’ COMMENT ’密碼’, PRIMARY KEY (`id`) USING BTREE) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;
5、在application.properties配置數據庫連接信息
#數據庫相關配置spring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useSSL=false&characterEncoding=utf8&allowMultiQueries=true&serverTimezone=Asia/Shanghai&useAffectedRows=truespring.datasource.username=rootspring.datasource.password=QQ796413#mybaits配置#mapper加載路徑mybatis.mapper-locations= classpath:mapper/*.xml#實體包位置mybatis.type-aliases-package= com.example.mybatisdemo.entity#myatbis配置文件mybatis.config-location= classpath:mybatis-config.xml
6、創建USER表對應的實體類
package com.example.mybatisdemo.entity;public class User { private int id; private String username; private String password; public int getId() {return id; } public void setId(int id) {this.id = id; } public String getUsername() {return username; } public void setUsername(String username) {this.username = username; } public String getPassword() {return password; } public void setPassword(String password) {this.password = password; } @Override public String toString() {return 'User{' +'id=' + id +', username=’' + username + ’’’ +', password=’' + password + ’’’ +’}’; }
7、在mapper/UserMapper創建UserMapper.java
package com.example.mybatisdemo.mapper;import com.example.mybatisdemo.entity.User;import org.apache.ibatis.annotations.Mapper;@Mapperpublic interface UserMapper{ User findUserById(Integer id);}
8、在service/UserService新建UserService.java
package com.example.mybatisdemo.service;import com.example.mybatisdemo.entity.User;public interface UserService { User findUserById(Integer id);}
9、在service/impl/UserServiceImpl 創建UserServiceImpl.java
package com.example.mybatisdemo.service.impl;import com.example.mybatisdemo.entity.User;import com.example.mybatisdemo.mapper.UserMapper;import com.example.mybatisdemo.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Servicepublic class UserServiceImpl implements UserService {@Autowiredprivate UserMapper userMapper;@Overridepublic User findUserById(Integer id) { return userMapper.findUserById(id);}}
10、在resources下新建mybatis-conf.xml
<?xml version='1.0' encoding='UTF-8' ?><!DOCTYPE configurationPUBLIC '-//mybatis.org//DTD Config 3.0//EN''http://mybatis.org/dtd/mybatis-3-config.dtd'><configuration> <settings><!--開啟日志--><setting name='logImpl' value='STDOUT_LOGGING'/><!--開啟駝峰命名法--><setting name='mapUnderscoreToCamelCase' value='true'/><!--開啟全局延遲加載--><setting name='lazyLoadingEnabled' value='true'/><!-- 集合為空時強制返回空集合實例而不是null --><setting name='returnInstanceForEmptyRow' value='true'/><!-- 結果集中value為空時保留key --><setting name='callSettersOnNulls' value='true'/> </settings></configuration>
11、在resources下mapper文件下創建UserMapper.xml
<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE mapper PUBLIC '-//mybatis.org//DTD Mapper 3.0//EN' 'http://mybatis.org/dtd/mybatis-3-mapper.dtd'><!--注意:1.這里的namespace要是你usermapper的位置--><mapper namespace='com.example.mybatisdemo.mapper.UserMapper'> <!--注意這里的返回類型--> <resultMap type='com.example.mybatisdemo.entity.User'><result column='id' property='id'/><result column='username' property='username'/><result column='password' property='password'/> </resultMap> <!--2.id和你的方法名一樣,resultMap為上面的id名一致--> <select resultMap='BaseResultMap'>select id, username, passwordfrom userwhere id= #{id,jdbcType=INTEGER} </select></mapper>
12、創建UserController.java
package com.example.mybatisdemo.controller;import com.example.mybatisdemo.entity.User;import com.example.mybatisdemo.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class UserController { @Autowired UserService userService; @GetMapping('/findUserById') public User findUserById(@RequestParam Integer id){ return userService.findUserById(1); }}
13、測試
工程可以去我的資源下載
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