如何实现android客户端与服务端数据同步

Question

android 数据同步

Answer 1

public class JSONDemoServlet extends HttpServlet {
private static final long serialVersionUID = -7368225680407826408L; 
private List<User> list;/**
* 处理post方式提交的数据
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}/**
* 处理get方式提交的数据
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/plain");
response.setCharacterEncoding("UTF-8");
PrintWriter out = response.getWriter();//准备用户数据 
prepareData();//JSON数组 
JSONArray array = new JSONArray();for(User bean:list){
//单个用户JSON对象 
JSONObject obj = new JSONObject(); 
try{obj.put("id", bean.getId());
obj.put("name", bean.getName());
obj.put("email", bean.getEmail());
obj.put("gender", bean.getGender()); 
}catch (Exception e) {
// TODO: handle exception
}
array.put(obj); 
} 
//输出 
out.write(array.toString()); 
out.flush(); 
out.close(); 
} 
private void prepareData()
{
list = new ArrayList<User>();
User bean1 = new User();
bean1.setId(1001); 
bean1.setName("Tony"); 
bean1.setEmail("[email protected]"); 
bean1.setGender("male"); 
list.add(bean1); User bean2 = new User();
bean2.setId(1002);
bean2.setName("Jack"); 
bean2.setEmail("[email protected]");
bean2.setGender("male"); 
list.add(bean2); User bean3 = new User();
bean3.setId(1003); 
bean3.setName("Marry");
bean3.setEmail("[email protected]");
bean3.setGender("female");
list.add(bean3);User bean4 = new User();
bean4.setId(1004); 
bean4.setName("Linda");
bean4.setEmail("[email protected]"); 
bean4.setGender("female"); 
list.add(bean4); 
}}
User.java
package com.test.Demo;public class User {
private int id;private String name;private String email;private String gender;public String getEmail() {
return email;
}public void setEmail(String email) {
this.email = email;
}public String getGender() {
return gender;
}public void setGender(String gender) {
this.gender = gender;
}public int getId() {
return id;
}public void setId(int id) {
this.id = id;
}public String getName() {
return name;
}public void setName(String name) {
this.name = name;
}}
web.xml中配置映射路径：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><servlet>
<servlet-name>JSONDemoServlet</servlet-name>
<servlet-class>com.test.Demo.JSONDemoServlet</servlet-class>
</servlet><servlet-mapping>
<servlet-name>JSONDemoServlet</servlet-name>
<url-pattern>/JSONDemoServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list></web-app>
客户端：
package com.test;import java.io.BufferedReader;
import java.io.InputStreamReader;import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.json.JSONArray;
import org.json.JSONObject;import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);try {
StringBuffer sb = new StringBuffer();
// 在测试过程中，经常是用本机做测试服务器，访问本机的IP地址要设置为10.0.2.2
String url = "http://10.0.2.2:8080/article/JSONDemoServlet";
String body = getContent(url);
JSONArray array = new JSONArray(body);
for (int i = 0; i < array.length(); i++) {
JSONObject obj = array.getJSONObject(i);
sb.append("id:").append(obj.getInt("id")).append("\t");
sb.append("name:").append(obj.getString("name")).append("\r\n");
sb.append("gender:").append(obj.getString("gender")).append(
"\t");
sb.append("email:").append(obj.getString("email")).append(
"\r\n");
sb.append("----------------------\r\n");
}
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText(sb.toString());
} catch (Exception e) {
// TODO: handle exception
}}private String getContent(String url) throws Exception {
StringBuilder sb = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpParams httpParams = client.getParams();// 设置网络超时参数
HttpConnectionParams.setConnectionTimeout(httpParams, 3000);
HttpConnectionParams.setSoTimeout(httpParams, 5000);
HttpResponse response = client.execute(new HttpGet(url));
HttpEntity entity = response.getEntity();
if (entity != null) {
BufferedReader reader = new BufferedReader(new InputStreamReader(
entity.getContent(), "UTF-8"), 8192);
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
reader.close();
}return sb.toString();
}}