package com.tszr.mango.core.page;

import java.util.List;

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.tszr.mango.common.utils.ReflectionUtils;

public class MybatisPageHelper {

    public static final String findPage = "findPage";

    /**
     * 分页查询, 约定查询方法名为 “findPage”
     * 
     * @param pageRequest 分页请求
     * @param mapper      Dao对象，MyBatis的 Mapper
     * @param args        方法参数
     * @return
     */
    public static PageResult findPage(PageRequest pageRequest, Object mapper) {
        return findPage(pageRequest, mapper, findPage);
    }

    /**
     * 调用分页插件进行分页查询
     * 
     * @param pageRequest     分页请求
     * @param mapper          Dao对象，MyBatis的 Mapper
     * @param queryMethodName 要分页的查询方法名
     * @param args            方法参数
     * @return
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static PageResult findPage(PageRequest pageRequest, Object mapper, String queryMethodName, Object... args) {
        // 设置分页参数
        int pageNum = pageRequest.getPageNum();
        int pageSize = pageRequest.getPageSize();
        PageHelper.startPage(pageNum, pageSize);
        // 利用反射调用查询方法
        Object result = ReflectionUtils.invoke(mapper, queryMethodName, args);
        return getPageResult(pageRequest, new PageInfo((List) result));
    }

    /**
     * 将分页信息封装到统一的接口
     * 
     * @param pageRequest
     * @param page
     * @return
     */
    private static PageResult getPageResult(PageRequest pageRequest, PageInfo<?> pageInfo) {
        PageResult pageResult = new PageResult();
        pageResult.setPageNum(pageInfo.getPageNum());
        pageResult.setPageSize(pageInfo.getPageSize());
        pageResult.setTotalSize(pageInfo.getTotal());
        pageResult.setTotalPages(pageInfo.getPages());
        pageResult.setContent(pageInfo.getList());
        return pageResult;
    }
}

package com.tszr.mango.core.page;

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

public class PageRequest {

    /**
     * 当前页码
     */
    private int pageNum = 1;
    /**
     * 每页数量
     */
    private int pageSize = 10;
    /**
     * 查询参数
     */
    private Map<String, Object> params = new HashMap<>();
    
    public int getPageNum() {
        return pageNum;
    }
    public void setPageNum(int pageNum) {
        this.pageNum = pageNum;
    }
    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    public Map<String, Object> getParams() {
        return params;
    }
    public void setParams(Map<String, Object> params) {
        this.params = params;
    }
    public Object getParam(String key) {
        return getParams().get(key);
    }
}

package com.tszr.mango.core.page;

import java.util.List;

public class PageResult {

    /**
     * 当前页码
     */
    private int pageNum;
    /**
     * 每页数量
     */
    private int pageSize;
    /**
     * 记录总数
     */
    private long totalSize;
    /**
     * 页码总数
     */
    private int totalPages;
    /**
     * 分页数据
     */
    private List<?> content;

    public int getPageNum() {
        return pageNum;
    }

    public void setPageNum(int pageNum) {
        this.pageNum = pageNum;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public long getTotalSize() {
        return totalSize;
    }

    public void setTotalSize(long totalSize) {
        this.totalSize = totalSize;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

    public List<?> getContent() {
        return content;
    }

    public void setContent(List<?> content) {
        this.content = content;
    }
}