advancedpagination.java

网上购物系统

package tarena.data;

import java.util.LinkedList;
import java.util.List;

/**
 * 高级分页类，考虑到当分页结果过多时，给分页的结果再次进行分页。
 */
public class AdvancedPagination extends SimplePagination {
	
	//允许同时显示的最大的页面数，默认为10
	private int maxshow = 10;
	
	//要显示的分页集合
	private List<Page> pages = null;

	public AdvancedPagination() {}
	
	/**
	 * @param total 	结果集中的总记录数
	 * @param every		每页要显示的个数
	 * @param current	当前第几页
	 * @param maxshow	分页最多显示几页
	 * @param url		分页链接
	 * @param param		分页信息在链接中的参数名称
	 */
	public AdvancedPagination(int total, int every, int current, int maxshow, String url, String param) {
		super(total, every, current, url, param);	
		this.setMaxshow(maxshow);
	}

	/**
	 * @param total 	结果集中的总记录数
	 * @param every		每页要显示的个数
	 * @param current	当前第几页
	 * @param maxshow	分页最多显示几页
	 * @param url		分页链接	 
	 */
	public AdvancedPagination(int total, int every, int current, int maxshow, String url) {
		super(total, every, current, url);	
		this.setMaxshow(maxshow);
	}

	public int getMaxshow() {
		return maxshow;
	}

	public void setMaxshow(int maxshow) {
		this.maxshow = maxshow>0?maxshow:this.maxshow;
	}

	@Override
	public int getTotal() {		
		return super.getTotal();
	}
	
	@Override
	public List<Page> getContent() {
		List<Page> content = null;
		try {
			if(this.pages != null) return this.pages;
			
			content = new LinkedList<Page>();

			int current = this.getCurrent();
			int half = this.maxshow%2==0?this.maxshow/2:this.maxshow/2+1;
			int totalpage = this.getTotalPage();
			
			int start = current - half + 1;
			int end = start + this.maxshow -1;
			
			//如果要显示的页面超出下限，显示前maxshow 页
			if(start<=1){
				start = 1;
				end = this.maxshow>totalpage?totalpage:this.maxshow;
			}
			//如果要显示的页面超出上限，显示后maxshow 页
			if(end>=totalpage){
				start = (totalpage - this.maxshow + 1)<1?1:(totalpage - this.maxshow + 1);
				end = totalpage;
			}
					
			for(int i=start;i<=end;i++){			
				content.add(new Page(i,this.getURLByPage(i)));			
			}
			if(this.getCurrent() - start < content.size()){				
				content.get(this.getCurrent()-start).setUrl(null);
			}
		} catch (RuntimeException e) {			
			e.printStackTrace();
		}
		
		return content;
	}	
	
	public Page getNext() {
		return super.getNext(null);
	}
	
	public Page getPrevious() {		
		return super.getPrevious(null);
	}
}