GAE&JDO by XMLHttpRequest()

基本上 和

Google App Engines Datastore with JDO ( GAE&JDO 1/7)) 這篇類似

不過在index.html 方面改用 XMLHttpRequest 呼叫server

範例網站 http://6.latest.catontest.appspot.com/


例子這裡就簡單的介紹三個功能

1. 新增
2. 查詢所有
3. 和更新三個功能

js 檔案格式如下

//-----------------------------------------------------
// 宣告 set httprequest by explorer
//-----------------------------------------------------
XmlsReq = false;
if(window.XMLHttpRequest) {
XmlsReq = new XMLHttpRequest();
} else if(window.ActiveXObject) {
try {
XmlsReq = new ActiveXObject("Msxml2.XMLHTTP"); // ie
} catch(e) {
XmlsReq = new ActiveXObject("Microsoft.XMLHTTP"); // ie
}
}


//----------------------------------------------------------
// 新增 PostHttpRequestAdd()
//----------------------------------------------------------
function PostHttpRequestAdd() {
// servlet name 記得要在web.xml 設定
var uri='add';

// 連接成功傳回訊息
XmlsReq.onreadystatechange=function() {
if (XmlsReq.readyState==4 && XmlsReq.status == 200) {
alert(XmlsReq.responseText);
}

}

// 取得輸入檔案的值
var aUserName = document.getElementById('aUserName').value;
var aUserPassword =document.getElementById('aUserPassword').value;
var aUserContent= document.getElementById('aUserContent').value;

// 設定要傳到server的值
var param = "aUserName="+aUserName+"&aUserPassword="+aUserPassword+"&aUserContent="+aUserContent;

// 以POST 方式 像server 傳送資料
XmlsReq.open("POST",uri,true);
XmlsReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
XmlsReq.send(param);
}


2. 查詢所有

//----------------------------------------------------------
// 新增 GetHttpRequestShow()
//----------------------------------------------------------
function GetHttpRequestShow() {
// servlet name 記得要在web.xml 設定
var uri='show';

// 連接成功傳回訊息
XmlsReq.onreadystatechange=function() {
if (XmlsReq.readyState==4 && XmlsReq.status == 200) {
alert(XmlsReq.responseText);
}
}

// 以GET方式 像server 傳送資料
XmlsReq.open("GET",uri,true);
XmlsReq.send(null);
}


//----------------------------------------------------------
// 新增 PostHttpRequest()
//----------------------------------------------------------
function PostHttpRequest() {
// servlet name 記得要在web.xml 設定
var uri='update';

// 連接成功傳回訊息
XmlsReq.onreadystatechange=function() {
if (XmlsReq.readyState==4 && XmlsReq.status == 200) {
alert(XmlsReq.responseText);
}

}

// 取得輸入檔案的值
var uUserName = document.getElementById('uUserName').value;
var uUserPassword =document.getElementById('uUserPassword').value;
var uUserContent= document.getElementById('uUserContent').value;

// 設定要傳到server的值
var param = "uUserName="+uUserName+"&uUserPassword="+uUserPassword+"&uUserContent="+uUserContent;


// 以POST 方式 像server 傳送資料
XmlsReq.open("POST",uri,true);
XmlsReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
XmlsReq.send(param);
}



三個功能的 server 端 檔案如下


//-----------------------------------------------------
// add.java
//-----------------------------------------------------
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import java.util.List;

import javax.jdo.PersistenceManager;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import jdo.cookie.example.PMF;
import jdo.cookie.example.User;

@SuppressWarnings("serial")
public class add extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws IOException {

/// get content
String UserName = req.getParameter("aUserName");
String UserPassword = req.getParameter("aUserPassword");
String UserContent = req.getParameter("aUserContent");

System.out.println(UserName);

/// Set new user
User newUesr=new User(UserName,UserPassword,UserContent );

/// Get Persistence Manager
PersistenceManager pm = PMF.get().getPersistenceManager();

/// check the name is already exist
String query = "select from " + User.class.getName() + " where Name == "+ "'"+UserName+"'";
List UserAll = (List) pm.newQuery(query).execute();

/// declare the output function,
/// out.println the html code in the client browser
PrintWriter out = resp.getWriter();

if(UserAll.isEmpty()){
out.println(newUesr.GetName());
/// add user in data store
pm.makePersistent(newUesr);
out.println("Success");
}
else
{
out.println("already exist");
}

}


}

//-----------------------------------------------------
// show.java
//-----------------------------------------------------

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.jdo.PersistenceManager;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import jdo.cookie.example.PMF;
import jdo.cookie.example.User;

@SuppressWarnings("serial")
public class show extends HttpServlet{
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {


/// set response type
resp.setContentType("text/plain");

/// get Persistence Manager
PersistenceManager pm = PMF.get().getPersistenceManager();

/// set query String
String query = "select from " + User.class.getName() ;

/// start query
List userAll = (List) pm.newQuery(query).execute();

/// declare the output function,
/// out.println the html code in the client browser
PrintWriter out = resp.getWriter();

/// check the data is exist or not
if(userAll.isEmpty()){
out.println("no data exist");
}
else
{
/// print all data name and content
for (User g : userAll) {
resp.getWriter().println(g.GetName()+" :"+" Content ="+g.GetContent());
}
}

}
}



//-----------------------------------------------------
// update .java
//-----------------------------------------------------
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.jdo.PersistenceManager;
import javax.jdo.Transaction;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import jdo.cookie.example.PMF;
import jdo.cookie.example.User;

public class update extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws IOException {

/// set response type
resp.setContentType("text/html;charset=UTF-8");
req.setCharacterEncoding("UTF-8");

/// get content
String UserName = req.getParameter("uUserName");
String UserPassword = req.getParameter("uUserPassword");
String UserContent = req.getParameter("uUserContent");

System.out.println(UserName);

/// get Persistence Manager
PersistenceManager pm = PMF.get().getPersistenceManager();

/// check the name is already exist
String query = "select from " + User.class.getName() + " where Name == "+ "'"+UserName+"'";
List UserAll = (List) pm.newQuery(query).execute();

/// declare the output function,
/// out.println the html code in the client browser
PrintWriter out = resp.getWriter();

/// declare Transaction when you update
Transaction tx = pm.currentTransaction();

try {

tx.begin();

/// get the User you want update
Iterator iter=UserAll.iterator();
User my_obj=(User)iter.next();

if (my_obj.GetPassword().equals(UserPassword))
{

my_obj.SetContent(UserContent); // Change the value
out.println("OK");
/// must be commit or will be do nothing
tx.commit();
}

}
catch (Exception e)
{
/// when no this data
if (tx.isActive())
{
out.println("sorry retry again");
tx.rollback();
}
}


}


}