获取网络上的json数据
2013-11-06 16:52
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1.新建一个web项目，使用json显示数据
(1)实体类News
News.java
(2)建立业务Bean
NewsService .java
（3）新建业务实现类(添加数据)
NewsServiceBean.java
(4)新建servlet
NewsListServlet.java
(5)jsp页面
News1.jsp（注意：ontentType="text/plain”）
<%@ page language="java" contentType="text/plain”; charset=utf-8"
pageEncoding="utf-8"%>
${json}
运行web项目，结果为：
注意：
我们新建一个jsp页面
News.jsp
Servlet调转到这个页面，结果为：
对比之后，发现调转到News.jsp页面后多出了红色部分。所以在android中json是无法解析的。所以不要调转News.jsp。
2.创建android项目，访问web
（1）添加网络访问权限
<category android:name="android.intent.category.LAUNCHER" />
（2）界面布局
Activity_main.xml
items.xml
(3)实体类
News.java
（4）工具类StreamTool.java 读取字节
（5)业务类
（7）MainActivity.java
Json获取数据结果：
(1)实体类News
News.java
package cn.com.entity;
public class News {
private Integer id;
private String title;
private Integer timelength;
public News(){};
public News(Integer id,String title,Integer timelength){
this.id= id;
this.title=title;
this.timelength=timelength;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Integer getTimelength() {
return timelength;
}
public void setTimelength(Integer timelength) {
this.timelength = timelength;
}
}(2)建立业务Bean
NewsService .java
package cn.com.Bean;
import java.util.List;
import cn.com.entity.News;
public interface NewsService {
public List<News> getLastNew();
}（3）新建业务实现类(添加数据)
NewsServiceBean.java
package cn.com.impl;
import java.util.ArrayList;
import java.util.List;
import cn.com.Bean.NewsService;
import cn.com.entity.News;
public class NewsServiceBean implements NewsService {
@Override
public List<News> getLastNew() {
List<News> newes = new ArrayList<News>();
newes.add(new News(12,"猫和老鼠",120));
newes.add(new News(14,"功夫小子",220));
newes.add(new News(11,"太极",120));
newes.add(new News(22,"nba总决赛",180));
newes.add(new News(15,"非诚勿扰",120));
return newes;
}
}(4)新建servlet
NewsListServlet.java
package cn.com.servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.com.Bean.NewsService;
import cn.com.entity.News;
import cn.com.impl.NewsServiceBean;
/**
* Servlet implementation class NewsListServlet
*/
public class NewsListServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private NewsService service = new NewsServiceBean();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<News> newes = service.getLastNew();//获取最新视频
//拼凑格式： [{id:20,title:"xxx",timelength:90},{id:20,title:"yyy",timelength:90}]
StringBuilder json = new StringBuilder();
json.append("[");
for(News news:newes){
json.append("{");
json.append("id:").append(news.getId()).append(",");
json.append("title:\"").append(news.getTitle()).append("\","); //title:"xxx"记得转义符
json.append("timelength:").append(news.getTimelength());
json.append("},");
}
json.deleteCharAt(json.length()-1); //去掉最好一个“,”号
json.append("]");
request.setAttribute("json", json.toString());
request.getRequestDispatcher("News1.jsp").forward(request, response);
}
}(5)jsp页面
News1.jsp（注意：ontentType="text/plain”）
<%@ page language="java" contentType="text/plain”; charset=utf-8"
pageEncoding="utf-8"%>
${json}
运行web项目，结果为：
注意：
我们新建一个jsp页面
News.jsp
<?xml version="1.0" encoding="utf-8" ?>
<%@ page language="java" contentType="text/plain; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Insert title here</title>
</head>
<body>
${json}
</body>
</html>Servlet调转到这个页面，结果为：
对比之后，发现调转到News.jsp页面后多出了红色部分。所以在android中json是无法解析的。所以不要调转News.jsp。
2.创建android项目，访问web
（1）添加网络访问权限
<category android:name="android.intent.category.LAUNCHER" />
（2）界面布局
Activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:android1="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ListView
android1:id="@+id/listView1"
android1:layout_width="match_parent"
android1:layout_height="wrap_content" >
</ListView>
</LinearLayout>items.xml
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<TextView
android:id="@+id/title"
android:layout_width="200dp"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/time"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>(3)实体类
News.java
package cn.com.entity;
public class News {
private Integer id;
private String title;
private Integer timelength;
public News(){};
public News(Integer id,String title,Integer timelength){
this.id= id;
this.title=title;
this.timelength=timelength;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Integer getTimelength() {
return timelength;
}
public void setTimelength(Integer timelength) {
this.timelength = timelength;
}
}（4）工具类StreamTool.java 读取字节
package cn.com.service;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class StreamTool {
public static String read(InputStream inputStream) throws IOException{
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
if((len=inputStream.read(buffer))!=-1){
os.write(buffer, 0, len);
}
byte[] data=os.toByteArray();
String json = new String(data);
os.close();
inputStream.close();
return json;
}
}（5)业务类
package cn.com.service;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONObject;
import cn.com.entity.News;
public class NewsService {
/**
* 得到 List<News>
* @return
* @throws Exception
*/
public static List<News> getJSONLastNews() throws Exception{
List<News> newes = null;
String path="http://10.162.0.171:8080/ServerForJSON/NewsListServlet";
URLurl = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)");
if(conn.getResponseCode()==200){
InputStream inputStream=conn.getInputStream();
newes = parseJSON(inputStream);//调用json方法获取json数据
}
return newes;
}
/**
* 获取json数据
* @param jsonStream
* @return
* @throws Exception
*/
public static List<News> parseJSON(InputStream jsonStream) throws Exception{
List<News> list = new ArrayList<News>();
String json = StreamTool.read(jsonStream);
JSONArray jsonArray = new JSONArray(json);
for(int i=0;i<jsonArray.length();i++){
JSONObject jsonObject = null;
jsonObject = jsonArray.getJSONObject(i);
int id = jsonObject.getInt("id");
String title = jsonObject.getString("title");
int time = jsonObject.getInt("timelength");
list.add(new News(id,title,time));
}
return list;
}
}（7）MainActivity.java
package com.example.getnewinjson;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import cn.com.entity.News;
import cn.com.service.NewsService;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class MainActivity extends Activity {
private ListView listView = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView1);
try { <pre name="code" class="java"> List<News> list = NewsService.getJSONLastNews();
List<Map<String,Object>> data = new ArrayList<Map<String,Object>>();
for(News news:list){
Map<String,Object> map = new HashMap<String, Object>();
map.put("id", news.getId());
map.put("title", "电影："+news.getTitle());
map.put("time", "时长："+news.getTimelength());
data.add(map);
}
Log.i("tag", data.toString());
SimpleAdapter adapter = new SimpleAdapter(MainActivity.this, data, R.layout.items, new String[]{"title","time"},
new int[]{R.id.title,R.id.time});
listView.setAdapter(adapter);
} catch (Exception e) { e.printStackTrace(); } }}<pre>Json获取数据结果：
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