Struts2+Android 使用struts2制作做webservice
看了一下黎老师的WebService,还是很典型的应用(黎老师的课程确实很棒啊!受益一生),可惜的是他用的struts做的 也是今天中午移植到struts2 也算是练手+重温了.
进正题>
做Struts2 首先是配置工程 这个很烦人,和Android比差的很远.
首先是
web.xml没什么好说的其实就是配置struts2
<?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"> <display-name></display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <!-- 定义核心Filter的名称 --> <filter-name>struts2</filter-name> <!--定义核心Filter的实现类 --> <filter-class> org.apache.struts2.dispatcher.FilterDispatcher </filter-class> </filter> <filter-mapping> <!--核心Filter的名称 --> <filter-name>struts2</filter-name> <!--使用该核心Filter来接受所有的Web请求 --> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
struts.xml相当于Android中的AndroidManifest.xm
l 就一个action,返回两个结果,json和xml 貌似Android中现在很流行json的WebService
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <package name="struts2" extends="struts-default"> <action name="List" class="com.su.action.VideoListAction"> <result name="xml">/videos.jsp</result> <result name="json">/jsonvideos.jsp</result> </action> </package> </struts>
<%@ page language="java" contentType="text/xml; charset=UTF-8" pageEncoding="UTF-8"%><%@taglib prefix="s" uri="/struts-tags"%><?xml version="1.0" encoding="UTF-8"?> <videos> <s:iterator value="#request.videos" id="video"> <video id="<s:property value="#video.id"/>"> <title><s:property value="#video.title"/></title> <timelength><s:property value="#video.time"/></timelength> </video> </s:iterator> </videos>
如果返回的是json那么是jsonviedos.jsp
<%@ page language="java" contentType="text/plain; charset=UTF-8" pageEncoding="UTF-8"%>${videos}
需要注意!xml文件中
<%@ page language="java" contentType="text/xml; charset=UTF-8" pageEncoding="UTF-8"%><%@taglib prefix="s" uri="/struts-tags"%><?xml version="1.0" encoding="UTF-8"?>
这里尖括号直接不要有空格不然在chrome里不能识别为xml文件 我想在解析的时候会报错(什么没有文件头什么的吧)
然后是java代码部分了
首先是VideoListAction.java也就是主action 相当于activity了
package com.su.action; import java.io.OutputStream; import java.io.PrintWriter; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; import com.su.domain.Video; import com.su.service.VideoService; import com.su.service.impl.VideoServiceBean; public class VideoListAction extends ActionSupport { private VideoService service = new VideoServiceBean(); private String format; public String getFormat() { return format; } public void setFormat(String format) { this.format = format; } @Override public String execute() throws Exception { List<Video> videos = service.getLastVideos(); if (format.equals("json")) { StringBuilder json = new StringBuilder(); json.append('['); for(Video video : videos){ // {id:76,title:"xxxx",timelength:80} json.append('{'); json.append("id:").append(video.getId()).append(','); json.append("title:\"").append(video.getTitle()).append("\","); json.append("timelength:").append(video.getTime()); json.append('}').append(','); } json.deleteCharAt(json.length()-1); json.append(']'); ServletActionContext.getRequest().setAttribute("videos", json); System.out.println("1111111111111111111111111111"); return "json"; } else { ServletActionContext.getRequest().setAttribute("videos", videos); return "xml"; } } }
很简单json就是从videos里拼接把String放到servleactioncontext ; xml就更简单了,直接返回的list
这个是video的bean Video.java
package com.su.domain; public class Video { private Integer id; private String title; private Integer time; public Video(){} public Video(Integer id, String title, Integer time) { this.id = id; this.title = title; this.time = time; } 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 getTime() { return time; } public void setTime(Integer time) { this.time = time; } }
这个是VideoServicebean.java获取videos 这个在真实使用的时候 数据是放在数据库的这个类就是来从数据库取出数据的,这里这是简单举例没有数据库
package com.su.service.impl; import java.util.ArrayList; import java.util.List; import com.su.domain.Video; import com.su.service.VideoService; public class VideoServiceBean implements VideoService { public List<Video> getLastVideos() throws Exception{ List<Video> videos = new ArrayList<Video>(); videos.add(new Video(78, "视频1", 90)); videos.add(new Video(78, "视频2", 20)); videos.add(new Video(78, "视频3", 30)); return videos; } }
VideoService.java定义的获取videos的接口
package com.su.service; import java.util.List; import com.su.domain.Video; public interface VideoService { public List<Video> getLastVideos() throws Exception; }
然后是Android端了这里就不详细介绍了,挺简单的解析json和xml这是黎老师的代码
主activity
package cn.itcast.videoclient; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import cn.itcast.domain.Video; import cn.itcast.service.VideoService; import android.app.Activity; import android.os.Bundle; import android.util.Log; import android.widget.ListView; import android.widget.SimpleAdapter; import android.widget.Toast; public class MainActivity extends Activity { private ListView listView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); listView = (ListView)this.findViewById(R.id.listView); try { List<Video> videos = VideoService.getJSONLastVideos(); List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>(); for(Video video : videos){ HashMap<String, Object> item = new HashMap<String, Object>(); item.put("id", video.getId()); item.put("title", video.getTitle()); item.put("timelength", "时长:"+ video.getTime()); data.add(item); } SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item, //放入了Adapter中 new String[]{"title", "timelength"}, new int[]{R.id.title, R.id.timelength}); listView.setAdapter(adapter); } catch (Exception e) { Toast.makeText(MainActivity.this, "获取最新视频资讯失败", 1).show(); Log.e("MainActivity", e.toString()); } } }
VideoService.java从服务器获取数据
package cn.itcast.service; 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 org.xmlpull.v1.XmlPullParser; import android.util.Xml; import cn.itcast.domain.Video; import cn.itcast.utils.StreamTool; public class VideoService { /** * 获取最新的视频资讯 * @return * @throws Exception */ public static List<Video> getLastVideos() throws Exception{ String path = "http://10.1.27.35:8080/VideoWeb2/List.action"; URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setReadTimeout(5*1000); conn.setRequestMethod("GET"); InputStream inStream = conn.getInputStream(); return parseXML(inStream); } public static List<Video> getJSONLastVideos() throws Exception{ List<Video> videos = new ArrayList<Video>(); String path = "http://10.1.27.35:8080/VideoWeb2/List.action?format=json"; URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setReadTimeout(5*1000); conn.setRequestMethod("GET"); InputStream inStream = conn.getInputStream(); byte[] data = StreamTool.readInputStream(inStream); String json = new String(data); JSONArray array = new JSONArray(json); for(int i=0 ; i < array.length() ; i++){ JSONObject item = array.getJSONObject(i); int id = item.getInt("id"); String title = item.getString("title"); int timelength = item.getInt("timelength"); videos.add(new Video(id, title, timelength)); } return videos; } /** * 解析服务器返回的协议,得到视频资讯 * @param inStream * @return * @throws Exception */ private static List<Video> parseXML(InputStream inStream) throws Exception{ List<Video> videos = null; Video video = null; XmlPullParser parser = Xml.newPullParser(); parser.setInput(inStream, "UTF-8"); int eventType = parser.getEventType();//产生第一个事件 while(eventType!=XmlPullParser.END_DOCUMENT){//只要不是文档结束事件 switch (eventType) { case XmlPullParser.START_DOCUMENT: videos = new ArrayList<Video>(); break; case XmlPullParser.START_TAG: String name = parser.getName();//获取解析器当前指向的元素的名称 if("video".equals(name)){ video = new Video(); video.setId(new Integer(parser.getAttributeValue(0))); } if(video!=null){ if("title".equals(name)){ video.setTitle(parser.nextText());//获取解析器当前指向元素的下一个文本节点的值 } if("timelength".equals(name)){ video.setTime(new Integer(parser.nextText())); } } break; case XmlPullParser.END_TAG: if("video".equals(parser.getName())){ videos.add(video); video = null; } break; } eventType = parser.next(); } return videos; } }
StreamTool.java 这个类是处理instream的
package cn.itcast.utils; import java.io.ByteArrayOutputStream; import java.io.InputStream; public class StreamTool { /** * 从输入流中获取数据输入一个input 输出一个byte[],获取的数据就可以通过new String(data)转换为String * @param inStream 输入流 * @return * @throws Exception */ public static byte[] readInputStream(InputStream inStream) throws Exception{ ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len=inStream.read(buffer)) != -1 ){ outStream.write(buffer, 0, len); } inStream.close(); return outStream.toByteArray(); } }
也有一个video.java
package cn.itcast.domain; public class Video {//video的bean private Integer id; private String title; private Integer time; public Video(){} public Video(Integer id, String title, Integer time) { this.id = id; this.title = title; this.time = time; } 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 getTime() { return time; } public void setTime(Integer time) { this.time = time; } }