繼續前篇學習,加入數據庫訪問層mybatis,這裏數據庫使用的是mysql
一,首先在原有的pom.xml中加入依賴:
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<!-- mybatis分頁工具,需要版本1.1.1及以上 -->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>4.1.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
這裏引入了mybaits分頁插件,PageHelper,是Github上以爲開發者提供的開源插件,使用很方便。
先看完整目錄結構:
二,在application.properties中配置數據源
#datasource
spring.datasource.url = jdbc:mysql://localhost:3306/yun?characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = centos
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10
spring.datasource.sql-script-encoding=UTF-8
三,創建測試tableCREATE TABLE `demo` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(20) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8
四,創建實體類Demopackage com.example.entity;
public class Demo {
private long id;
private String name;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
五,創建接口DemoMapper,這裏先採用註解方式實現,注意接口上不需要添加註解package com.example.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Select;
import com.example.entity.Demo;
public interface DemoMapper {
@Select("select * from demo where name = #{name}")
public List<Demo> likeName(String name);
@Select("select * from demo where id = #{id}")
public Demo getById(long id);
}
六,創建DemoService + DemoServiceImpl
package com.example.service;
import java.util.List;
import com.example.entity.Demo;
public interface DemoService {
public List<Demo> likeName(String name);
public Demo getById(long id);
}
package com.example.service.impl;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import com.example.entity.Demo;
import com.example.mapper.DemoMapper;
import com.example.service.DemoService;
@Service
public class DemoServiceImpl implements DemoService {
@Resource
private DemoMapper demoMapper;
@Override
public List<Demo> likeName(String name) {
return demoMapper.likeName(name);
}
@Override
public Demo getById(long id) {
return demoMapper.getById(id);
}
}
七,創建DemoController
package com.example.controller;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import com.example.entity.Demo;
import com.example.service.DemoService;
@RestController
public class DemoController {
@Resource
private DemoService demoService;
@RequestMapping(value="/demo/list",method=RequestMethod.GET)
public List<Demo> list(String name){
return demoService.likeName(name);
}
}
八,啓動類DemoApplication添加註解,掃描mapper
package com.example;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.*.mapper")//掃描該包下接口
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
九,啓動測試
http://localhost:8088/spring-boot/demo/list?name=test
返回結果如下(預先在數據庫插入了4條數據,便於測試):
[
{
"id": 1,
"name": "test"
},
{
"id": 2,
"name": "test"
},
{
"id": 3,
"name": "test"
},
{
"id": 4,
"name": "test"
}
]
十,使用分頁插件,通過@Bean註解注入package com.example.config;
import java.util.Properties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.github.pagehelper.PageHelper;
@Configuration
public class PageHelperConfiguration {
@Bean
public PageHelper pageHelper() {
PageHelper pageHelper = new PageHelper();
Properties p = new Properties();
p.setProperty("offsetAsPageNum", "true");
p.setProperty("rowBoundsWithCount", "true");
p.setProperty("reasonable", "true");
pageHelper.setProperties(p);
return pageHelper;
}
}
十一,DemoController新增分頁方法@RequestMapping(value="/demo/page",method=RequestMethod.GET)
public List<Demo> page(String name){
PageHelper.startPage(1,2);
return demoService.likeName(name);
}
十二,訪問測試
http://localhost:8088/spring-boot/demo/page?name=test
返回結果如下:
[
{
"id": 1,
"name": "test"
},
{
"id": 2,
"name": "test"
}
]
=================================================================================================
以上是採用註解方式實現sql語句,下面採用常規的xml配置方式
十三,新增DemoMapper.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" >
<mapper namespace="com.example.mapper.DemoMapper" >
<resultMap id="BaseResultMap" type="com.example.entity.Demo" >
<id column="id" property="id" jdbcType="BIGINT" />
<result column="name" property="name" jdbcType="VARCHAR" />
</resultMap>
<sql id="Base_Column_List" >
id, name
</sql>
<select id="selectAll" resultMap="BaseResultMap" >
select
<include refid="Base_Column_List" />
from demo
</select>
<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long" >
select
<include refid="Base_Column_List" />
from demo
where id = #{id,jdbcType=BIGINT}
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.Long" >
delete from demo
where id = #{id,jdbcType=BIGINT}
</delete>
</mapper>
十四,接口中添加相應的方法
DemoMapper
int deleteByPrimaryKey(Long id);
Demo selectByPrimaryKey(Long id);
List<Demo> selectAll();
DemoServiceint deleteByPrimaryKey(Long id);
Demo selectByPrimaryKey(Long id);
List<Demo> selectAll();
DemoServiceImpl@Override
public int deleteByPrimaryKey(Long id) {
return demoMapper.deleteByPrimaryKey(id);
}
@Override
public Demo selectByPrimaryKey(Long id) {
return demoMapper.selectByPrimaryKey(id);
}
@Override
public List<Demo> selectAll() {
return demoMapper.selectAll();
}
十五,DemoController @RequestMapping(value="/demo/all",method=RequestMethod.GET)
public List<Demo> all(){
PageHelper.startPage(1,2);
return demoService.selectAll();
}
@RequestMapping(value="/del",method=RequestMethod.DELETE)
public int del(long id){
return demoService.deleteByPrimaryKey(id);
}
@RequestMapping(value="/demo",method=RequestMethod.GET)
public Demo get(long id){
return demoService.selectByPrimaryKey(id);
}
十六,方法都寫好了,最主要是在application.properties中註冊*.xml的目錄,添加如下配置:
#mapper.xml location
mybatis.mapperLocations=classpath:mybatis/mapper/*.xml
mybatis.config-locations=classpath:mybatis/mybatis-config.xml
注意這裏配置的mybatis-config.xml主要是配置了別名,可以不用,這裏加上作爲補充知識點,方便以後使用十七,測試,注意分頁插件依然生效,測試結果如下:
mybaits的使用到此結束,下篇繼續學習sping_boot爲我們提供的數據庫訪問層,SpringBoot 學習記錄(三): jpa