Spring boot-SpringBoot分页插件PageHelper

深碍√TFBOYSˉ_ 2021-10-09 10:16 422阅读 0赞

## 1.添加pom文件依赖 ##

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    
    
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.1</version>
    </dependency>
    
    
    <dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper-spring-boot-starter</artifactId>
        <version>1.2.2</version>
    </dependency>
    
    
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.3</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

## 2.配置application.yml ##

# 与mybatis整合
    mybatis:
      config-location: classpath:mybatis.xml
      mapper-locations:
      - classpath:mapper/*.xml
    
    # 分页配置
    pagehelper:
      helper-dialect: mysql
      reasonable: true
      support-methods-arguments: true
      params: count=countSql

## 3.service层中使用插件 ##

package com.ahut.serviceImpl;
    
    import java.util.List;
    
    import javax.servlet.ServletContext;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    import org.springframework.web.context.ContextLoader;
    
    import com.ahut.entity.GoodsType;
    import com.ahut.mapper.GoodsTypeMapper;
    import com.ahut.service.GoodsTypeService;
    import com.github.pagehelper.PageHelper;
    
    /**
     * 
     * @ClassName: GoodsTypeServiceImpl
     * @Description: 商品类型业务逻辑处理
     * @author cheng
     * @date 2017年7月17日 上午10:04:31
     */
    @Service
    @Transactional(rollbackFor = { RuntimeException.class, Exception.class })
    public class GoodsTypeServiceImpl implements GoodsTypeService {
        // 数据访问
        @Autowired
        private GoodsTypeMapper typeDao;
    
        /**
         * 
         * @Title: getList
         * @Description: 从数据库中获取所有商品类型列表
         * @param pageNum 当前页
         * @param pageSize 当前页面展示数目
         * @return
         * @throws Exception
         */
        public List<GoodsType> getList(int pageNum, int pageSize) throws Exception {
            //使用分页插件,核心代码就这一行
            PageHelper.startPage(pageNum, pageSize);
            // 获取
            List<GoodsType> typeList = typeDao.getList();
            return typeList;
        }
    
    }

## 4.controller层代码 ##

package com.ahut.action;
    
    import java.util.List;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.ahut.entity.GoodsType;
    import com.ahut.service.GoodsTypeService;
    
    /**
     * 
     * @ClassName: GoodsTypeAction
     * @Description: 商品类型控制层
     * @author cheng
     * @date 2017年7月17日 上午11:09:47
     */
    @RestController // 等价于@Controller+@ResponseBody
    public class GoodsTypeAction {
        // 业务逻辑
        @Autowired
        private GoodsTypeService typeService;
    
        /**
         * 
         * @Title: getGoodsTypeList
         * @Description: 获取商品类型列表
         * @return
         * @throws Exception
         */
        @RequestMapping(value = "/getGoodsTypeList")
        public List<GoodsType> getGoodsTypeList(int pageNum, int pageSize) throws Exception {
            // 调用业务逻辑,返回数据
            return typeService.getList(pageNum,pageSize);
        }
    
    }

## 5.测试 ##

已知我数据库中有九条数据：

![这里写图片描述][SouthEast]

正常情况：

**1.显示第一页或者第二页数据**  
请求url：

http://localhost:8080/getGoodsTypeList?pageNum=1&pageSize=4

返回数据：

[
        {
            "typeId": "708cc61c6a9811e796dee09467355fab",
            "typeName": "全部",
            "createTime": 1500258859000,
            "updateTime": 1500621762000
        },
        {
            "typeId": "98f8a04e6a9811e796dee09467355fab",
            "typeName": "考研资料",
            "createTime": 1500258927000,
            "updateTime": null
        },
        {
            "typeId": "b720c87f6a9811e796dee09467355fab",
            "typeName": "交通工具",
            "createTime": 1500258978000,
            "updateTime": null
        },
        {
            "typeId": "cbe3c2326a9811e796dee09467355fab",
            "typeName": "生活用品",
            "createTime": 1500259013000,
            "updateTime": 1500626046000
        }
    ]

***结论：当请求页数小于第一页时，显示第一页数据***

**2.显示的页数大于最后一页（显示最后一页数据）**  
pageNum > 最后一页

请求url：

http://localhost:8080/getGoodsTypeList?pageNum=4&pageSize=4

返回数据：

[
        {
            "typeId": "d992195f6df111e7bab4e09467355fab",
            "typeName": "测试2改变了",
            "createTime": 1501145516000,
            "updateTime": 1500716178000
        }
    ]

***结论：当请求页面大于最后一页时，显示最后一页数据***

[SouthEast]: /images/20211009/2f461c8344294e1fafbc11ca6b1762cd.png