SpringBoot学习四：整合Mybatis分页插件 PageHelper

引入maven依赖

按照惯例，需要引入SpringBoot的pagehelper依赖。

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.2.3</version>
</dependency>

请注意版本号，与Mybatis不兼容的版本号可能会导致异常

配置pagehelper参数

#mybatis配置
mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: online.suiyu.mybatisdemo.entity
server:
  port: 8083
#配置pagehelper
pagehelper:
  helper-dialect: mysql
  reasonable: true
  support-methods-arguments: true
  params: count=countSql

详细配置参数参考官方文档

依次修改Controller、Service，添加分页的参数

1. Controller层

@ApiOperation(value = "getAllUser", notes = "获取所有的内容", tags = "user")
@RequestMapping(value = "/getalluser", method = RequestMethod.GET)
public List<User> getAllUser(@RequestParam(value = "pageNum", required = false, defaultValue = "1") int pageNum,
                             @RequestParam(value = "pageSize", required = false, defaultValue = "4") int pageSize) {
    return userService.getAllUser(pageNum, pageSize);
}

2. Service层

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public List<User> getAllUser(int pageNum, int pageSize) {
        //这是整个过程中最核心的一条语句
        PageHelper.startPage(pageNum, pageSize);
        return userMapper.getAllUser();
    }
}

到此完成，顺便一提，当pageNum<=0时，加载第一页，当pageNum>最后一页则加载最后一页。这是有配置文件中的reasonable: true决定的！

到此，整合完成！