dbpages-new.java

自己整理的一些java工具类包括文件处理

package com.reason.util;

import java.util.*;
import javax.servlet.http.*;
import org.apache.torque.*;
import org.apache.torque.util.*;
import com.workingdogs.village.*;

/**
 * <p>Title: DBPages</p>
 * <p>Description: Peer==>DBPages==>listData==>pageHTML</p>
 * 输入数据: RunData("page_sql","page_index","page_size","page_url")
 * 输出数据: RunData("page_list","page_html")
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: pubinfo</p>
 * @author chineseren
 * @version 1.0
 */

public class DBPages {
  //分页时将数据list存放到rd中是用到的key
  public static final String KEY_PAGE_SQL = "page_sql"; //查询的sql
  public static final String KEY_PAGE_INDEX = "page_index"; //开始的页号
  public static final String KEY_PAGE_SIZE = "page_size"; //页面大小
  public static final String KEY_PAGE_URL = "page_url"; //分页动作Handler不包括参数,比如:"/webapps/ActHandler"
  public static final String KEY_PAGE_HTML = "page_html"; //生成的html
  public static final String KEY_PAGE_LIST = "page_list"; //当前页的list
  public static final int PAGE_SIZE = 10; //默认的分页大小
  private RunData rd; //传入的RunData
  private List list;//查询到的当前页的数据rundatas
  private String html;//生成的页面html
  private int totalRecords; //查询sql所能获得的记录总数

  public RunData getRd(){
    return rd;
  }
  public List getList(){
    return list;
  }
  public String getHtml(){
    return html;
  }

  /**
   * 对外开放的分页入口
   * @param rd RunData("page_sql","page_index","page_size","page_url")
   * @return DBPages RunData("page_list","page_html")
   */
  public static DBPages doPage(RunData rd) {
    DBPages pager = new DBPages(rd);
    //查询数据 && 返回结果
    rd.put(KEY_PAGE_LIST, pager.getPageList());
    rd.put(KEY_PAGE_HTML, pager.getPageHtml());
    return pager;
  }

  public DBPages(RunData rd) {
    this.rd = rd;
  }

  public void setIndex(int index) {
    rd.put(KEY_PAGE_INDEX,index);
  }

  public void setTotalRecords(int totalRecords) {
    this.totalRecords = totalRecords;
  }

  public void setPageSize(int pageSize) {
    rd.put(KEY_PAGE_SIZE,pageSize);
  }

  //当前页面大小
  public int getPageSize() {
    return rd.getInt(KEY_PAGE_SIZE,PAGE_SIZE);
  }

  //取得所有记录的条数
  public int getTotalRecords() {
    return this.totalRecords;
  }

  //取得所有的页数
  public int getTotalPages() {
    return(totalRecords + getPageSize() - 1) / getPageSize();
  }

  //得到当前页号
  public int getIndex() {
    return rd.getInt(KEY_PAGE_INDEX,1);
  }

  //是否有上一页
  public boolean hasPreviousPage() {
    if(1 >= this.getIndex()) {
      return false;
    } else {
      return true;
    }
  }

  //是否有下一页
  public boolean hasNextPage() {
    if(this.getTotalPages() <= this.getIndex()) {
      return false;
    } else {
      return true;
    }
  }

  //取得上一页号
  public int getPreviousIndex() {
    if(this.hasPreviousPage()) {
      return (this.getIndex() - 1);
    } else {
      return this.getIndex();
    }
  }

  //取得下一页号
  public int getNextIndex() {
    if(this.hasNextPage()) {
      return (this.getIndex() + 1);
    } else {
      return this.getIndex();
    }
  }

  //取得首页号
  public int getFirstIndex() {
    return 1;
  }

  //取得最后页号
  public int getLastIndex() {
    return this.getTotalPages();
  }

  //以下的是获取当前分页信息,设置为public是为了外部实现不同的分页外观
  public List getPageList() {
    String sql = null;
    String strCount = null;
    List ls = null;
    Record tc = null;
    int index = 1; //页码从1开始,记录号从0开始
    int size = 10; //页面大小

    sql = rd.getString(KEY_PAGE_SQL);
    Debug.debug("DBPages.getPageList() input SQL is:\n" + sql);
    sql = sql.trim();
    String tempSql = sql.toUpperCase();
    strCount = "SELECT COUNT(*) as C FROM "
        + sql.substring(tempSql.indexOf(" FROM ") + 6, sql.length());
    tempSql = null;
    Debug.debug("DBPages.getPageList() Count(*) SQL is:\n" + strCount);

    //取得分页记录集,出错返回null
    try {
      ls = BasePeer.executeQuery(strCount);
      tc = (Record)ls.get(0);
      this.setTotalRecords(tc.getValue("C").asInt()); //所有记录数
      Debug.debug("DBPages.getPageList() totalRecord is: " + this.totalRecords);
    } catch(Exception ex) {
      Debug.error("DBPages.getPageList() get COUNT ERROR!", ex);
      return null;
    }
    try {
      index = rd.getInt(KEY_PAGE_INDEX, 1);
      index = (1 > index) ? 1 : index;
      this.setIndex(index);
      size = rd.getInt(KEY_PAGE_SIZE, PAGE_SIZE);
      size = (1 > size) ? PAGE_SIZE : size;
      this.setPageSize(size);
      this.list = BasePeer.executeQuery(sql, (index - 1) * size, size,
          Torque.getDefaultDB(), false);
      this.list = RunData.recordListToRunDataList(this.list);
      int count = (null == list) ? 0 : this.list.size();
      Debug.debug("DBPages.getPageList() LIST is: " + count);
    } catch(Exception ex) {
      Debug.error("DBPages.getPageList() get LIST ERROR!", ex);
      return null;
    }
    return list;
  }

  //根据RunData中的参数得到分页后的完整的url，并去掉index参数
  public String getPageUrl() {
    StringBuffer url = new StringBuffer(rd.getString(KEY_PAGE_URL));
    url.append("?"); //开始取request中的参数
    HttpServletRequest request = rd.getRequest();
    Enumeration keys = request.getParameterNames();
    while(keys.hasMoreElements()) {
      String key = (String)keys.nextElement();
      String value = request.getParameter(key);
      if(value != null && !key.equals(KEY_PAGE_INDEX)) {
        url.append(key);
        url.append("=");
        url.append(java.net.URLEncoder.encode(value));
        url.append("&");
      }
    }
    //等待补充index参数
    url.append(KEY_PAGE_INDEX);
    url.append("=");
    return url.toString().substring(0, url.length());
  }

  //获取page_html: "共25条记录 第2/3页(每页10条)  << < 1 2 3 > >>_go"
  public String getPageHtml() {
    //参数
    String url = this.getPageUrl();
    StringBuffer sb = new StringBuffer();
    //共25条记录 第2/3页(每页10条)
    sb.append("共").append(this.getTotalRecords()).append("条记录 第")
        .append(this.getIndex()).append("/").append(this.getTotalPages())
        .append("页(每页").append(this.getPageSize()).append("条)");
    //<< <
    if(this.hasPreviousPage()) {
      sb.append("<a href='").append(url).append(this.getFirstIndex())
          .append("'> &lt;&lt; </a>");
      sb.append("<a href='").append(url).append(this.getPreviousIndex())
          .append("'> &lt; </a>");
    } else {
      sb.append(" &lt;&lt; ");
      sb.append(" &lt; ");
    }
    //1 2 3
    int count = this.getTotalPages();
    for (int i = 1; i <= count; i++) {
      sb.append("<a href='").append(url).append(i)
          .append("'> ").append(i).append(" </a>");
    }
    //> >>
    if(this.hasNextPage()) {
      sb.append("<a href='").append(url).append(this.getNextIndex())
          .append("'> &gt; </a>");
      sb.append("<a href='").append(url).append(this.getLastIndex())
          .append("'> &gt;&gt; </a>");
    } else {
      sb.append(" &gt; ");
      sb.append(" &gt;&gt; ");
    }
    //_go
    sb.append("<input type='text' size='2' maxLength='2' name='goIndex' value='");
    sb.append(this.getNextIndex());
    sb.append("'><input type='button' value='Go' onClick=javascript:window.location='");
    sb.append(url);
    sb.append("'+");
    sb.append("document.all.goIndex.value;>");

    this.html = sb.toString();
    return this.html;
  }
}