值里面存放的是一个对象需要根据id排序 将相同的人放在一起
List<Map.Entry<String, CorrectRate>> list =
new LinkedList<Map.Entry<String, CorrectRate>>(correctRateOm.entrySet());
Collections.sort(list, new Comparator<Map.Entry<String, CorrectRate>>() {
public int compare(Map.Entry<String, CorrectRate> o1, Map.Entry<String, CorrectRate> o2) {
return (o1.getValue().getStudentId()).compareTo(o2.getValue().getStudentId());
}
});
java对list进行分页 业务场景因为数据是通过从数据库中多次sql查出来之后存放到list 无法使用sql进行分页
package com.unote.echarts.entity;
import java.util.List;
/**
* @program: unote
* @description: list分页工具类
* @author: cuixy
* @create: 2019-09-27 09:37
**/
public class PageModel {
private int page = 1; // 当前页
public int totalPages = 0; // 总页数
private int pageRecorders;// 每页5条数据
private int totalRows = 0; // 总数据数
private int pageStartRow = 0;// 每页的起始数
private int pageEndRow = 0; // 每页显示数据的终止数
private boolean hasNextPage = false; // 是否有下一页
private boolean hasPreviousPage = false; // 是否有前一页
private List list;
// private Iterator it;
public PageModel(List list, int pageRecorders) {
init(list, pageRecorders);// 通过对象集,记录总数划分
}
/** */
/**
* 初始化list,并告之该list每页的记录数
*
* @param list
* @param pageRecorders
*/
public void init(List list, int pageRecorders) {
this.pageRecorders = pageRecorders;
this.list = list;
totalRows = list.size();
// it = list.iterator();
hasPreviousPage = false;
if ((totalRows % pageRecorders) == 0) {
totalPages = totalRows / pageRecorders;
} else {
totalPages = totalRows / pageRecorders + 1;
}
if (page >= totalPages) {
hasNextPage = false;
} else {
hasNextPage = true;
}
if (totalRows < pageRecorders) {
this.pageStartRow = 0;
this.pageEndRow = totalRows;
} else {
this.pageStartRow = 0;
this.pageEndRow = pageRecorders;
}
}
// 判断要不要分页
public boolean isNext() {
return list.size() > 5;
}
public void setHasPreviousPage(boolean hasPreviousPage) {
this.hasPreviousPage = hasPreviousPage;
}
public String toString(int temp) {
String str = Integer.toString(temp);
return str;
}
public void description() {
String description = "共有数据数:" + this.getTotalRows()
+ "共有页数: " + this.getTotalPages()
+ "当前页数为:" + this.getPage()
+ " 是否有前一页: " + this.isHasPreviousPage()
+ " 是否有下一页:" + this.isHasNextPage()
+ " 开始行数:" + this.getPageStartRow()
+ " 终止行数:" + this.getPageEndRow();
System.out.println(description);
}
public List getNextPage() {
page = page + 1;
disposePage();
System.out.println("用户凋用的是第" + page + "页");
this.description();
return getObjects(page);
}
/** */
/**
* 处理分页
*/
private void disposePage() {
if (page == 0) {
page = 1;
}
if ((page - 1) > 0) {
hasPreviousPage = true;
} else {
hasPreviousPage = false;
}
if (page >= totalPages) {
hasNextPage = false;
} else {
hasNextPage = true;
}
}
public List getPreviousPage() {
page = page - 1;
if ((page - 1) > 0) {
hasPreviousPage = true;
} else {
hasPreviousPage = false;
}
if (page >= totalPages) {
hasNextPage = false;
} else {
hasNextPage = true;
}
this.description();
return getObjects(page);
}
/** */
/**
* 获取第几页的内容
*
* @param page
* @return
*/
public List getObjects(int page) {
if (page == 0) {
this.setPage(1);
} else {
this.setPage(page);
}
this.disposePage();
if (page * pageRecorders < totalRows) {// 判断是否为最后一页
pageEndRow = page * pageRecorders;
pageStartRow = pageEndRow - pageRecorders;
} else {
pageEndRow = totalRows;
pageStartRow = pageRecorders * (totalPages - 1);
}
List objects = null;
if (!list.isEmpty()) {
objects = list.subList(pageStartRow, pageEndRow);
}
//this.description();
return objects;
}
public List getFistPage() {
if (this.isNext()) {
return list.subList(0, pageRecorders);
} else {
return list;
}
}
public boolean isHasNextPage() {
return hasNextPage;
}
public void setHasNextPage(boolean hasNextPage) {
this.hasNextPage = hasNextPage;
}
public List getList() {
return list;
}
public void setList(List list) {
this.list = list;
}
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public int getPageEndRow() {
return pageEndRow;
}
public void setPageEndRow(int pageEndRow) {
this.pageEndRow = pageEndRow;
}
public int getPageRecorders() {
return pageRecorders;
}
public void setPageRecorders(int pageRecorders) {
this.pageRecorders = pageRecorders;
}
public int getPageStartRow() {
return pageStartRow;
}
public void setPageStartRow(int pageStartRow) {
this.pageStartRow = pageStartRow;
}
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
public int getTotalRows() {
return totalRows;
}
public void setTotalRows(int totalRows) {
this.totalRows = totalRows;
}
public boolean isHasPreviousPage() {
return hasPreviousPage;
}
}
调用方法
PageModel pm = new PageModel(list, Integer.parseInt(page_size));//每页显示条数
List sublist = pm.getObjects(Integer.parseInt(page_no));//显示第几页
data.put("list", sublist);
data.put("total_count", list.size());
data.put("page_no", Integer.parseInt(page_no));
data.put("page_size", Integer.parseInt(page_size));