springBoot+mybatis(demo)

结构:

build.gradle

buildscript {
    ext {
        springBootVersion = '2.0.4.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'war'

group = 'com.spring'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}
dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    compile('org.mybatis.spring.boot:mybatis-spring-boot-starter:1.3.2')
    runtime('org.postgresql:postgresql')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    compile('org.projectlombok:lombok:1.18.2')
}

create database

create table d_user (id varchar, username varchar, password varchar, email varchar)

application.yml

server:
  port: 8085

spring:
  datasource:
    url: jdbc:postgresql://{ip}/{databaseName}
    username: postgres
    password: p
    type: com.zaxxer.hikari.HikariDataSource
    driver-class-name: org.postgresql.Driver

mybatis:
  mapper-locations: classpath:mapping/*.xml
  type-aliases-package: com.spring.model

创建实体model User.java

• 采用 lombok, 节省getter setter
• Alias() 作用于UserMapper.xml 的 resultType (如果没有注解默认是model 的小写)

package com.spring.model;

import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.apache.ibatis.type.Alias;

/**
 * @author derrick.liang
 */
@Getter
@Setter
@ToString
@Alias(value = "User")
public class User {
    private String id;
    private String username;
    private String password;
    private String email;

    public User(String id, String username, String password, String email) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.email = email;
    }

    public User() {
    }
}

创建Mapper 接口 UserMapper.java

package com.spring.mapper;
import com.spring.model.User;
import org.apache.ibatis.annotations.Mapper;
/**
 * @author derrick.liang
 */
@Mapper
public interface UserMapper {
    User findUserByUsernam username);
}

创建 UserMapper.xml 映射文件

<?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">
<mapper namespace="com.spring.mapper.UserMapper">
    <select id="findUserByUsername" resultType="User">
        select * from d_user where username = #{username}
    </select>
</mapper>

Dao

UserDao.java

package com.spring.dao;

import com.spring.model.User;

import java.util.Optional;

/**
 * @author derrick.liang
 */
public interface UserDao {
    Optional<User> findUserByUsername(String username);
}

UserDaoImpl.java

package com.spring.dao;

import com.spring.mapper.UserMapper;
import com.spring.model.User;
import org.springframework.stereotype.Repository;

import javax.annotation.Resource;
import java.util.Optional;

/**
 * @author derrick.liang
 */
@Repository
public class UserDaoImpl implements UserDao {
    @Resource
    UserMapper userMapper;

    @Override
    public Optional<User> findUserByUsername(String username) {
        User user = userMapper.findUserByUsername(username);
        return Optional.ofNullable(user);
    }
}

Service

UserService.java

package com.spring.service;

import com.spring.model.User;

import java.util.Optional;

/**
 * @author derrick.liang
 */
public interface UserService {
    Optional<User> findUserByName(String username);
}

UserServiceImpl.java

package com.spring.service;

import com.spring.dao.UserDao;
import com.spring.model.User;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Optional;

/**
 * @author derrick.liang
 */
@Service
public class UserServiceImpl implements UserService {
    @Resource
    UserDao userDao;

    @Override
    public Optional<User> findUserByName(String username) {
        Optional<User> optionalUser = userDao.findUserByUsername(username);
        User user = optionalUser.orElse(new User());
        user.setId("test");
        return Optional.of(user);
    }
}

Controller

UserController.java

package com.spring.controller;

import com.spring.model.User;
import com.spring.service.UserService;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @author derrick.liang
 */
@RestController
@RequestMapping("/api")
public class UserController {
    @Resource
    UserService userService;

    @RequestMapping("/get/{username}")
    public User getUserInfo(@PathVariable(value = "username") String username) {
        return userService.findUserByName(username).orElse(new User());
    }
}

Application

package com.spring;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(MybatisApplication.class, args);
    }
}

确保webapp 可以部署到Tomcat， 需要实现自定义ServletContainerInitializer 配置加载

ServletInitializer.java

package com.spring;

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

/**
 * @author derrick.liang
 */
public class ServletInitializer extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(MybatisApplication.class);
    }
}

postman 测试

需要注意的点

• 当指定了@service/@repository的name值时， 在@Resource中要么不指示，如果指示的话，则要与之相对应。
• 当没有指定@service的name值是，在@Resource中随意。但是前提是，实现该接口的只有这一个类。
• 所以，建议是最好在@service/@repository和@Resoure中同时指定名称，并且做到一一对应。
• 如果采用@Autowired来注解，则同样无需指定name属性，若是实现该接口有多个类，则需要通过@Qualifier来做区分