SpringBoot2.0.3+Mybatis-Plus2.3+pagehelper 实现分页功能

 1.配置 pom.xml，引入相关 jar

    4.0.0

    com.rent.merchant
    MerchantManage
    1.0-SNAPSHOT

    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.3.RELEASE
    

    
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
        
            mysql
            mysql-connector-java
            5.1.24
            jar
            compile
        

        
        
            com.baomidou
            mybatisplus-spring-boot-starter
            1.0.5
        
        
            com.baomidou
            mybatis-plus
            2.3
        

        
        
            com.github.pagehelper
            pagehelper-spring-boot-starter
            1.2.9
        

        
        
            org.projectlombok
            lombok
            true
        
    

    
        1.8
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

    
        
            spring-releases
            https://repo.spring.io/libs-release
        
    

    
        
            spring-releases
            https://repo.spring.io/libs-release
        
    

2.编写主函数Application：

package com.rent.merchant;

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);
    }
}

3.编写接口

    /**
     * merchant list
     *
     * @param withdraw
     * @return ResultStruct
     * @author liumengwei
     * @date 2018/10/17
     * @since V1.0
     */
    @RequestMapping(value = "/merchantList", method = RequestMethod.GET, produces = "application/json; charset=utf-8")
    @ResponseBody
    public ResultStruct merchantList(
            @Param ("page") int page,
            @Param ("limit") int limit,
            @Param ("merchantName") String merchantName,
            @Param ("idnumber") String idnumber,
            @Param ("telephone") String telephone,
            @Context HttpServletRequest request) {
        try {
            Map map = new HashMap<>();
            map.put("merchantName", merchantName);
            map.put("idnumber", idnumber);
            map.put("telephone", telephone);
            map.put("limit", limit);
            map.put("page", page);
            List list = merchantService.merchantList(map);
            map.clear();
            map.put("item", list);
            return ResultStruct.setResultStructInfo(map, ResultMsgConstant.querySuccess, ResultStruct.OK);
        } catch (Exception ex) {
            return SystemException.setResult(ex, logger);
        }
    }

4.创建实体类

package com.rent.merchant.daoBean;

import lombok.Data;

@Data
public class Merchant {
    private Long id;
    private String password;
    private String merchantName;
    private String businessLicense;
    private String businessLicenseNumber;
    private String address;
    private String bossName;
    private String idnumber;
    private String telephone;
    private String bankNumber;
    private String commissionRate;
    private String subtopic;
    private String insertTime;
    private int delete;
    private int level;
    private String qccode;
}

5.编写mapper

使用@SelectProvider 注解方式获取 sql

package com.rent.merchant.mapper;

import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.rent.merchant.daoBean.Merchant;
import com.rent.merchant.provider.MerchantMapperProvider;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.SelectProvider;

import java.util.List;
import java.util.Map;

@Mapper
public interface MerchantMapper extends BaseMapper {
    @Results({
            @Result(property = "insertTime", column = "insert_time"),
            @Result(property = "merchantName", column = "merchant_name"),
            @Result(property = "businessLicense", column = "business_license"),
            @Result(property = "bossName", column = "boss_name"),
            @Result(property = "commissionRate", column = "commission_rate"),
            @Result(property = "bankNumber", column = "bank_number"),
            @Result(property = "businessLicenseNumber", column = "business_license_number")
    })
    @SelectProvider(type = MerchantMapperProvider.class, method = "merchantList")
    List merchantList(Map map);
}

package com.rent.merchant.provider;

import com.rent.merchant.common.utils.StringUtil;

import java.util.HashMap;
import java.util.Map;

public class MerchantMapperProvider {
    public String merchantList(Map map) {
        StringBuffer sql = new StringBuffer(
                "select m.* from t_merchant m where 1=1 "
        );
        Map sqlMap = new HashMap<>();
        sqlMap.put("merchantName", " and m.merchant_name like '%" + map.get("merchantName") + "%'");
        sqlMap.put("telephone", " and m.telephone like '%" + map.get("telephone") + "%'");
        sqlMap.put("idnumber", " and m.idnumber like '%" + map.get("idnumber") + "%'");
        for (Map.Entry mm : map.entrySet()) {
            if (!StringUtil.isEmpty(mm.getValue())) {
                if (sqlMap.get(mm.getKey()) != null)
                    sql.append(sqlMap.get(mm.getKey()));
            }
        }
        return sql.toString();
    }

}

6.编写 Service

package com.rent.merchant.service;

import com.github.pagehelper.PageHelper;
import com.rent.merchant.common.page.PageBean;
import com.rent.merchant.daoBean.Merchant;
import com.rent.merchant.mapper.MerchantMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;

@Service
public class MerchantService {
    @Autowired
    private MerchantMapper merchantMapper;

    /**
     * merchant list
     *
     * @return ResultStruct
     * @author liumengwei
     * @date 2018/10/12
     * @since V1.0
     */
    public List merchantList(Map map) {
        int currentPage = Integer.parseInt(String.valueOf(map.get("page")));
        int pageSize = Integer.parseInt(String.valueOf(map.get("limit")));
        PageHelper.startPage(currentPage, pageSize);
        List withdrawBeanList = merchantMapper.merchantList(map);
        int countNums = withdrawBeanList.size();
        PageBean pageData = new PageBean<>(currentPage, pageSize, countNums);
        pageData.setItems(withdrawBeanList);
        return pageData.getItems();
    }

}

至此，既可使用pagehelper实现分页功能

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