Struts2，oracle实现GOOGLE的分页样式

BAIDU的搜索

我的实现，跟google的是一样的，没有像百度一样加载20条

要修改的地方分为三处：Pager.java,Action,jsp

Pager.java

是用来存储各种页面属性以及定义输出到页面的分页样式的。

Action

则是将数据库里面的数据查询出来，然后将其传输到页面，当然还有Pager.java里面的输出样式也在这里面传输到页面。

jsp

取出数据显示

viewSource

pager.java

/**
 * @author Atlas Email:generationrent@gmail.com
 *
 */
public class Pager {
	private int current;// 当前记录的位置
	private int size; // 数据总记录
	private int length;// 每页显示的记录条数
	private String url;// URL 调用Action里分页请求的URL
	private String pageHeader;// 导航条前文字

	public Pager(int offset, int size, int length,String url,  String pageHeader) {
		this.current = offset;
		this.size = size;
		this.length = length;
		this.url = url;
		this.pageHeader = pageHeader;
	}

	public int getOffset() {
		return current;
	}

	public void setOffset(int offset) {
		this.current = offset;
	}

	public int getSize() {
		return size;
	}

	public void setSize(int size) {
		this.size = size;
	}

	public int getLength() {
		return length;
	}

	public void setLength(int length) {
		this.length = length;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public String getPageHeader() {
		return pageHeader;
	}

	public void setPageHeader(String pageHeader) {
		this.pageHeader = pageHeader;
	}

	/**
	 * 返回分页导航条
	 * 
	 */

	public String getPageNavigation() {
		String pageNavigation = ""; 
		
		if (size > length) {
			String pref; // 前缀
			if (url.indexOf("?") > -1) {
			 
				pref = "&";
			} else {
				 
				pref = "?";
			}
			 
			if (pageHeader != null && pageHeader.length() > 0) {
				pageNavigation = pageHeader + " : ";
			}
			//  包含“<<”(第一页)和“<”(前一页)
			if (current > 0) {
				pageNavigation += "<a href='" + url + pref
						+ "current=0'>[首页]</a>\n" + "<a href='" + url + pref
						+ "current=" + (current - length) + "'>[<]</a>\n";
			}
			// 导航条中,排头的那一页的current值
			int startOffset;
			
			int radius = Constants.MAX_PAGE_INDEX / 2 * length;
			
			if (current < radius
					|| this.pageCount() <= Constants.MAX_PAGE_INDEX) {
				
				startOffset = 0;
			} else if (current < size - radius) {
				startOffset = current - radius;
			} else {
				startOffset = (size / length - Constants.MAX_PAGE_INDEX)
						* length;
			}
			for (int i = startOffset; i < size
					&& i < startOffset + Constants.MAX_PAGE_INDEX * length; i += length) {
				if (i == current) {
					// 当前页号,加粗显示
					pageNavigation += "<b>" + (i / length + 1) + "</b>\n";
				} else {
					
					pageNavigation += "<a href='" + url + pref + "current=" + i
							+ "'>" + (i / length + 1) + "</a>\n";
				}
			}
			//(下一页)和“>>”(最后一页)
			if (current < size - length) {
				pageNavigation += "<a href='" + url + pref + "current="
						+ (current + length) + "'>[>]</a>\n" + "<a href='"
						+ url + pref + "current=" + lastPageOffset()
						+ "'>[尾页]</a>\n";
			}
			
			return pageNavigation;
		}
		
		else {
			return "";
		}
		//return "";
	}

	/**
	 * 返回分页后的总页数
	 * 
	
	 */
	public int pageCount() {
		int pagecount = 0;
		if (size % length == 0) {
			pagecount = size / length;
		} else {
			pagecount = size / length + 1;
		}
		return pagecount;
	}

	/**
	 * 返回最后一页的起始记录位置
	
	 */
	public int lastPageOffset() {
		return size - lastPageSize();
	}

	/**
	 * 返回最后一页的记录数
	
	 */
	public int lastPageSize() {
		int lastpagesize = 0;
		if (size % length == 0) {
			lastpagesize = length;
		} else {
			lastpagesize = size % length;
		}
		return lastpagesize;
	}
}

action

/**
 * 用户基本信息管理 控制器
 * 
 * @author Atlas Email:generationrent@gmail.com
 * */@Controller@Scope(value = "protoType")@Action(value = "userbaseAction", results = {@Result(name = "success", location = "/jsp/user.jsp") })public class UserBaseInfoMangeAction extends ActionSupport implementsServletRequestAware
 {private int current;// 起始记录的位置/** * @return the current */public int getCurrent() {return current;}/** * @param current * the current to set */public void setCurrent(int current) {this.current = current;}// 获得requestprivate HttpServletRequest request;// inject
 beanprivate UserBase userbase;/** * @return the userbase */public UserBase getUserbase() {return userbase;}/** * @param userbase * the userbase to set */public void setUserbase(UserBase userbase) {this.userbase = userbase;}/** * */private static final long
 serialVersionUID = 1L;/** * 注入 service */@ResourceUserBaseService userbaseService;public void setServletRequest(HttpServletRequest request) {this.request = request;}/** * 查询所有 * * @return */public String query() {// pagination beginfinal int offset = this.getCurrent();final
 int pagesize = Constants.PAGE_SIZE;// pagination end// 获得所有用户信息List<UserBase> list = this.userbaseService.queryUserBaseInfos(offset,pagesize);final int size = this.userbaseService.getRsUserBaseCount();//请求地址final String url =Constants.QUERY_PATH;Pager p =
 new Pager(offset, size, pagesize, url, "");request.setAttribute("pager", p);request.setAttribute("userbaseInfosList", list);return SUCCESS;}

Conastants.java 


/**
 * @author Atlas Email:Generationrent@gmail.com
 *
 */
public class Constants {

	/**
	 * 页面显示的数字 最大到10 1...10
	 */
	public static int MAX_PAGE_INDEX = 10;
	

	/**
	 * 每页的记录数
	 */
	public static int PAGE_SIZE = 10;
	/**
	 * 分页 查询地址
	 */
	public static String QUERY_PATH = "http://127.0.0.1:8088/alllig/userbaseAction!query";
}
Dao


@Repository
public class UserBaseDaoImpl implements UserBaseDao {
	/*
	 * (non-Javadoc)
	 * 
	 * @see com.travelsky.ism.dao.UserBaseDao#queryUserBaseInfos()
	 */
	@Override
	public List<UserBase> queryUserBaseInfos(int offset, int length) {
		List<UserBase> infoList = null;
		EntityManager em = null;
		try {
			em = JpaUtil.getEntityManger();
			final String jpaQl = "select userbase from UserBase userbase";
			Query q = em.createQuery(jpaQl);
			// 设置起始记录数
			q.setFirstResult(offset);
			// 查询多少条记录
			q.setMaxResults(length);
			// 获得结果集
			infoList = q.getResultList();

			for (int i = 0; i < infoList.size(); i++) {
				System.out.println(infoList.get(i).getUsername());
			}

		} finally {
			if (null != em) {
				em.close();
			}
		}

		return infoList;
	}

	@Override
	public int getRsUserBaseCount() {
		Number count = 0;
		EntityManager em = null;
		try {
			final JpaTemplate jpaTemplate = new JpaTemplate(
					Persistence.createEntityManagerFactory("jpaname"));
			// 获得记录条数
			String COUNT_ALL = "select count(*) from UserBase";
			count = (Number) jpaTemplate.find(COUNT_ALL).get(0);

		} finally {
			if (null != em) {
				em.close();
			}
		}
		return count.intValue();
	}
}
jsp
<%@ page import="com.travelsky.ism.util.Pager"%>

<s:iterator var="pager">
		<jsp:useBean id="pager" type="com.travelsky.ism.util.Pager"   scope="request" />
		<jsp:getProperty name="pager" property="pageNavigation" />查询结果<p>
		<br /> 共有记录<jsp:getProperty name="pager" property="size" />条
		<br /> 每页有<jsp:getProperty name="pager" property="length" />条记录
		<br />
</s:iterator>


REFERENCES:http://www.oschina.net/code/snippet_251973_9435