mybatis有两种方式，一种是基于XML，一种是基于注解

springboot集成mybatis

首先先创建表，这里都简化了

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (

`id` int(11) NOT NULL auto_increment,

`username` varchar(255) default NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

INSERT INTO `user` VALUES ('1', 'lijia');

然后创建maven项目，在pom.xml中添加

org.springframework.boot

spring-boot-parent

1.5.4.RELEASE

1.8

UTF-8

UTF-8

org.springframework.boot

spring-boot-starter-web

org.mybatis.spring.boot

mybatis-spring-boot-starter

1.3.0

mysql

mysql-connector-java

runtime

org.springframework.boot

spring-boot-devtools

true

com.alibaba

fastjson

1.2.31

org.projectlombok

lombok

provided

org.springframework.boot

spring-boot-maven-plugin

true

XML形式

目录结构是

application.properties

# jdbc_config

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.url=jdbc:mysql://172.16.255.69:3306/test?characterEncoding=utf8

spring.datasource.username=root

spring.datasource.password=root

# Mybatis

#mybatis.typeAliasesPackage对应的是实体类位置

mybatis.typeAliasesPackage=org.lijia.bean

#mybatis.mapperLocations查找mybatis配置文件位置

mybatis.mapperLocations=classpath:mybatis/*.xml

实体类User

public class User {

private String id; //用户id

private String username; //用户名

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

}

HelloController ：

import com.alibaba.fastjson.JSON;

import com.lijia.bean.User;

import com.lijia.service.HelloService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.ResponseBody;

@Controller

@RequestMapping("/hello")

public class HelloController {

@Autowired

private HelloService helloService;

@RequestMapping("/get")

@ResponseBody

public String get(@RequestParam String username){

User user = helloService.get(username);

if(user!=null){

System.out.println("user.getName():"+user.getUsername());

}

return JSON.toJSONString(user);

}

@RequestMapping("/exception")

@ResponseBody

public String exception(){

throw new RuntimeException();

}

}

HelloService ：

import com.lijia.bean.User;

import com.lijia.dao.HelloMapper;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

@Service

//@Transactional

public class HelloService {

@Autowired

private HelloMapper helloMapper;

public User get(String username) {

return helloMapper.findUserByName(username);

}

}

接口HelloMapper ：

import com.lijia.bean.User;

public interface HelloMapper {

public User findUserByName(String username);

}

mybatis配置文件：

select * from user where username = #{username}

最后启动类Application：

import org.mybatis.spring.annotation.MapperScan;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

@MapperScan("com.lijia.dao") //扫描接口

public class Application {

public static void main(String[] args) {

SpringApplication.run(Application.class,args);

}

}

启动Application,输入成功获取数据

mybatis注解方式

注解方式我感觉太简单了，一般我也是用这个

没有了mybatis那些配置文件

application.properties:去除了mybatis的东西

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.url=jdbc:mysql://172.16.255.69:3306/test?characterEncoding=utf8

spring.datasource.username=root

spring.datasource.password=root

启动类Application：也没有了扫描

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class Application {

public static void main(String[] args) {

SpringApplication.run(Application.class,args);

}

}

最主要的是：HelloMapper

import com.lijia.bean.User;

import org.apache.ibatis.annotations.Mapper;

import org.apache.ibatis.annotations.Select;

@Mapper

public interface HelloMapper {

@Select("select * from user where username = #{username}")

public User findUserByName(String username);

}

在接口上加上@Mapper

在方法上面加上@Select里面跟着sql

然后启动Application，结果一样

全局异常捕获

只要在项目中加上这个类

import com.lijia.common.result.Result;

import com.lijia.common.result.ResultEnum;

import org.springframework.web.bind.annotation.ControllerAdvice;

import org.springframework.web.bind.annotation.ExceptionHandler;

import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;

/**

* Desc:全局异常捕获并返回

*

*/

@RestController

@ControllerAdvice

public class ExceptionHandlerController {

@ExceptionHandler(Exception.class)

public Result defaultExceptionHandler(HttpServletRequest request, Exception e)

throws Exception {

return new Result<>(ResultEnum.SERVER_ERROR, e.getMessage());

}

}

这里面的Result是自定义。

import com.fasterxml.jackson.annotation.JsonInclude;

import lombok.Data;

import lombok.NoArgsConstructor;

@Data

@JsonInclude(JsonInclude.Include.NON_NULL)

@NoArgsConstructor

public class Result {

private int code;

private String desc;

private T data;

public Result(ResultEnum resultEnum) {

this.code = resultEnum.getCode();

this.desc = resultEnum.getDesc();

}

public Result(ResultEnum resultEnum, T data) {

this.code = resultEnum.getCode();

this.desc = resultEnum.getDesc();

this.data = data;

}

}

还有个枚举

public enum ResultEnum {

SUCCESS(200, "success"), SERVER_ERROR(500, "server error");

private int code;

private String desc;

ResultEnum(int code, String desc) {

this.code = code;

this.desc = desc;

}

public int getCode() {

return code;

}

public String getDesc() {

return desc;

}

}

在上面的Controller中已经有异常的方法，启动Application