js前台分页显示后端JAVA数据响应_javascript技巧

好久没有写过代码了，手有些痒了，正好底下小弟们某些功能的实现着实影响工程进度，便自己动手给写了一段。

功能：js前台分页显示 + 后台数据响应(JAVA Servlet即可)
框架：jquery1.8.7
此文目的：给那些刚入行软件开发，喜欢这也看看，那也看看，这儿copy一下，那儿copy一下初级小菜鸟们做一个表帅;
1 为程序者需认真踏实坐下来;
2 程序需要有投入才有收获;
3 有收获才有鼓舞，才有动力一步一步往下走！

下面上代码，具体会有小注释
1、web页面的逻辑处理(js代码写到页面里时，有个好处，调试时不会受js文件缓存的影响)

采购单状态:

-search all!-
未结
部分
已结

2 后台页面响应的JAVA代码(即一个标准的Servlet)

package com.ljb.ttt.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ljb.ttt.impl.BasicDao;
public class AllCheckAction extends HttpServlet {
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doPost(req, resp);
}
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
try {
int executetype = -1;
String types = req.getParameter("executetype");
if(types == null)
return;
else
executetype = Integer.valueOf(types);
PrintWriter out = resp.getWriter();
BasicDao bd = new BasicDao();
switch(executetype){
case 5:
String orderStatus = req.getParameter("orderstatus");
Integer page = Integer.valueOf(req.getParameter("page"));
Integer pageSize = Integer.valueOf(req.getParameter("pagerows"));
String condition = "";
String content = "";
Integer wholePages = 0;
if(orderStatus != null && (!orderStatus.equals(""))){
condition = String.format(" and orderstatus='%s'",orderStatus);
}
int wholeSize = bd.count("`order` t1,worker t2", pageSize," and t1.wid=t2.wid" +
condition+" and t1.orid in (select orid from orderdetail)");
if(0 == wholeSize%pageSize)
wholePages = wholeSize/pageSize;
else
wholePages = wholeSize/pageSize + 1;
//对于不正确页的判断处理
if (page >= wholePages)
page = wholePages;
if(pagepage = 1;
condition += String.format(" limit %d,%d",pageSize*(page-1),pageSize);
content = String.format("{\"ContentBody\":[{\"page\":\"%d\",\"wholepage\":\"%d\",\"searchtext\":\""+condition+"\"}]}",
page,wholePages);
out.print(content);
System.out.println(content);
break;
//for OrderClose.jsp in get order data
case 6:
String sconditon = (String)req.getParameter("scondition");
if(sconditon != null){
if(sconditon.equals(""))
out.print(getJsonData(6, "", "Orders",bd));
else
out.print(getJsonData(6, sconditon, "Orders",bd));
}
break;
default:
break;
}
out.flush();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
//generate data from a search sql
private String getJsonData(int type,String searchContent,String jsonName,BasicDao bd){
String sql = "";
switch(type){
//获取
case 6:
sql = String.format("select t1.orid,t2.wname,t1.date,t1.remark,t1.orderstatus from `order` t1,worker t2 where t1.wid=t2.wid" +
" and t1.orid in (select orid from orderdetail)%s",searchContent);
break;
default:
break;
}
String temp = bd.getJsonStr(sql,jsonName);
// System.out.println(temp);
return temp;
}
}

3 让Servlet在web.xml中的配置参考

CheckSaveServlet
com.ljb.ttt.servlet.CheckSaveServlet


CheckSaveServlet
/CheckSaveServlet

4 付上本次后台调用的一个关键方法，将查询转化为JSON数据格式的方法

//return DataType {"tittle":[{"colName":"val",..},{},{}]}
public String getJsonStr(String sql,String jsonName){
String jsonStr = "";
String tjson = "";
Connection con = null;
ResultSet rs = null;
PreparedStatement pst = null;
con = sh.getConnection();
HashMap hm = sh.select(con, pst, rs, sql, null);
rs = (ResultSet)hm.get("ResultSet");
int colNum;
try {
colNum = rs.getMetaData().getColumnCount();
String colName[] = new String[colNum];
for(int i= 0;icolName[i] = rs.getMetaData().getColumnName(i+1);
while(rs.next()){
jsonStr += "{";
String temp = "";
for(int i= 0;itemp += "\"";
temp += colName[i];
temp += "\":\"";
temp += rs.getString(i+1);
temp += "\",";
}
jsonStr += temp.substring(0, temp.length()-1);
jsonStr += "},";
}
tjson += "{\""+jsonName + "\":[";
if(jsonStr!="")
tjson += jsonStr.substring(0, jsonStr.length()-1);
tjson += "]}";
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
pst = (PreparedStatement)hm.get("PreparedStatement");
sh.closeAll(rs, pst, con);
return tjson;
}

注：
1 里面没有见到过的方法调用，不用担心，搞过java连接数据库的都没有问题；
2 这个里面有一个比较不足的地方，将页数信息与页面数据分两次AJAX请求得到，这个是非常影响性能的，如果能做到将一次ajax请求，一次解析获取全部需要数据，那就比较出彩了(嵌套JSON就是不错的选择)。
3 由于并非专职搞web开发，发现这个CSS样式搭配起来还是非常费劲的。
最后贴个效果图上来：