关于java:Java工程师高薪训练营十二阶段版

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import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class ListPageUtil<T> {

 /** * 每页显示条数 */private int pageSize; /** * 总页数 */private int pageCount; /** * 原汇合 */private List<T> data;public ListPageUtil(List<T> data, int pageSize) {    if (data == null || data.isEmpty()) {        throw new IllegalArgumentException("data must be not empty!");    }    this.data = data;    this.pageSize = pageSize;    this.pageCount = data.size()/pageSize;    if(data.size()%pageSize!=0){        this.pageCount++;    }}/** * 失去分页后的数据 * * @param pageNum 页码 * @return 分页后后果 */public List<T> getPagedList(int pageNum) {    int fromIndex = (pageNum - 1) * pageSize;    if (fromIndex >= data.size()) {        return Collections.emptyList();    }    int toIndex = pageNum * pageSize;    if (toIndex >= data.size()) {        toIndex = data.size();    }    return data.subList(fromIndex, toIndex);}public int getPageSize() {    return pageSize;}public List<T> getData() {    return data;}public int getPageCount() {    return pageCount;}public static void main(String[] args) {    Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};    List<Integer> list = Arrays.asList(array);    ListPageUtil<Integer> pager = new ListPageUtil<Integer>(list, 10);        System.out.println(pager.getPageCount());    List<Integer> page1 = pager.getPagedList(1);    System.out.println(page1);    List<Integer> page2 = pager.getPagedList(2);    System.out.println(page2);    List<Integer> page3 = pager.getPagedList(3);    System.out.println(page3);}

}