JAVA8的分页工具
内容摘要
使用JAVA8的API可以实现分页,在数据量相对稳定的情况下,可以查出所有数据,配合缓存使用import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
/*
import java.util.List;
import java.util.Optional;
/*
文章正文
使用JAVA8的API可以实现分页,在数据量相对稳定的情况下,可以查出所有数据,配合缓存使用
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | import java.util.ArrayList; import java.util.List; import java.util.Optional; /** * @version 1.0 * @author levelmini * @param <T> */ public class Page<T> { private int current_page; private int size; private int total_page; private int total_sum; private transient List<T> instanceList; //Gson不序列化transient字段 private List<T> currentPageData; private transient Optional<List<T>> op; public Page(List<T> instanceList,int size) { this.size = size; setInstanceList(instanceList); } public int getCurrent_page() { return current_page; } public void setCurrent_page(int current_page) { this.current_page = current_page<1?1:current_page>this.total_page?this.total_page:current_page; setCurrentPageData(currentPageData()); } public int getSize() { return size; } public void setSize(int size) { this.size = size; } public int getTotal_page() { return total_page; } public int getTotal_sum() { return total_sum; } public List<T> getInstanceList() { return instanceList; } public void setInstanceList(List<T> instanceList) { this.op= Optional.ofNullable(instanceList); this.instanceList = op.orElse( new ArrayList<T>()); this.total_sum = this.instanceList.size(); this.total_page =(int) Math. ceil (1.0*this.total_sum/this.size); } public void setCurrentPageData(List<T> currentPageData) { this.currentPageData = currentPageData; } public List<T> getCurrentPageData(){ return this.currentPageData; } private List<T> currentPageData(){ if (this.size==0 || this.total_page == 1){ return this.instanceList; } List<T> currentPageData = new ArrayList<T>(); instanceList.stream().skip((this.current_page-1)*this.size).limit(this.size).forEach(e->currentPageData.add(e)); return currentPageData; } } |
用法:
1 2 3 4 | List<News> newsList = newsService.findAll(); Page<News> page = new Page<>(newsList, size); page.setCurrent_page(current_page); return JsonUtil.toJson(page, "yyyy-MM-dd" ); |
代码注释
[!--zhushi--]