前面相继介绍了Android网络编程里的Socket传输图片、HttpURLConnection,今天看HttpClient.
第一部分：JavaEE版的Eclipse配置Tomcat
【备注:开发后台server用Eclipse的JavaEE版最好的，但单就Tomcat来说(不写jsp之类的)，本文以下的server方面操作在普通版的Eclipse也是能够的。
我这里为了和ADT-bundle分开。特意又一次安个JavaEE版的Eclipse。】
1、下载Eclipse的Tomcat插件:http://www.eclipsetotale.com/tomcatPlugin.html 将其解压得到com.sysdeo.eclipse.tomcat_3.3.0目录。
将它拷贝到eclipse的plugins目录下。
重新启动Eclipse会看到上面有三个小猫，哈哈
2、下载apache-tomcat-7.0.53-windows-x86 最新到8.0了，但Eclipse支持貌似最高7.0，所以还是用7.0。解压apache-tomcat-7.0.53-windows-x86至C盘根目录，配置环境变量，新增CATALINA_HOME 路径为:C:\apache-tomcat-7.0.53 或者直接将这个变量配置到Path里都ok。
然后双击bin目录下的startup脚本。浏览器输入:http://localhost:8080/ 看到小猫表示windows上的tomcat配好了。
3、新建一个javaproject，在里面选择Tomcat Projectproject如图所看到的:
配置Tomcat和Server选项：
watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQveWFuemkxMjI1NjI3/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />
watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQveWFuemkxMjI1NjI3/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />
备注:新建project这块也能够在Web里选择新建Dynamic Web Project，这是标准的使用Servlet、JSP等技术开发动态站点的项目。须要JavaEE版的Eclipse。
第二部分：联通浏览器和Tomcat
即在浏览器输入一个网址。tomcat里返回一句话，浏览器收到并显示。
之所以弄这一步一是为了測试，二是后来会发现。Android里的HttpClient就跟这个浏览器一样。
1.在WEB-INF/src目录下新建包名org.yanzi.testtomcat,在里面新建一个类TestTomcat继承自HttpServlet.并重写里面的doGet方法。
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
resp.setContentType("text/html;charset=utf-8");
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
PrintWriter out = resp.getWriter();
// //用HTML格式给浏览器返回数据
// out.println("<html>");
// out.println("<head>");
// out.println("<title>Hello,Servlet!</title>");
// out.println("</head>");
// out.println("<body>");
// out.println("Hello,First Servlet!");
// out.println("</body>");
// out.println("</html>");
out.println("Hello,第一个Tomcat!!!");
out.close();
}
2.在WEB-INF目录下新建文件wem.xml，内容例如以下：
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app >
<servlet>
<servlet-name>test_yan</servlet-name>
<!-- 名字随便 -->
<servlet-class>org.yanzi.testtomcat.TestTomcat</servlet-class>
<!-- servlet类名 -->
</servlet>
<servlet-mapping>
<servlet-name>test_yan</servlet-name>
<url-pattern>/login</url-pattern>
<!-- url訪问虚拟路径，最后我们就是通过project名/login进行訪问的。像这样http://127.0.0.1:8000/LoginAction/login -->
</servlet-mapping>
</web-app>
关于上面的配置注意:a. servlet-name是servlet的名字，这个名字能够随便起。
仅仅要servlet-name标签里名字一样就能够了。b. servlet-class里写包名+类名。c. url-pattern这里也是随便写的，是输入浏览器里的地址。本博文中浏览器的地址是:
http://localhost:8080/TestTomcat/login 这里的8080是端口，是在tomcat安装文件中的conf里的server.xml配置好的。用默认的就ok。除非此端口已被其它占用。
TestTomcat这里指的是project的名字。而非类的名字。最后的“/login”跟web.xml里相应，注意后面不要再多加一个斜杠成这样"/login/", 这是解析不了的。
3. 改动conf目录下的tomcat-users.xml文件。在里面加入一个用户:
<role rolename="manager"/>
<user username="admin" password="admin" roles="manager"/>
默认的都是全被凝视掉的。
然后就能够点击eclipse上的小猫头像。开启这个servlet服务了。浏览器输入http://localhost:8080/TestTomcat/login 能够看到:
watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQveWFuemkxMjI1NjI3/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />
在doGet()函数里用html格式输出，即：
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
resp.setContentType("text/html;charset=utf-8");
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
PrintWriter out = resp.getWriter();
//用HTML格式给浏览器返回数据
out.println("<html>");
out.println("<head>");
out.println("<title>Tomcat Servlet測试</title>");
out.println("</head>");
out.println("<body>");
out.println("Hello,First Servlet!");
out.println("</body>");
out.println("</html>");
out.println("Hello,第一个Tomcat!!!");
out.close();
}
看到效果:
这是由于用html格式给它设置了标题名字，并打印了一句话。
这里真想吐槽一下，最初我用百度浏览器倒置了两个小时都没有出来。后来在google浏览器里一输入就ok了。
真心坑爹啊。
另外，假设浏览器在看视频。貌似也是出不来的。
大爷的。此点么深究！
。
第三部分:重写TestTomcat里的doPost()和doGet()方法。
由于我准备再手机上用doPost跟Tomcat通信。传递一个username和password。Tomcat推断后再返回结果。改好后的TestTomcat.java的完整文件例如以下:
package org.yanzi.testtomcat;
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;
public class TestTomcat extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final int NAME_CODE_RIGHT = 0; //
private static final int CODE_WRONG = 1; //
private static final int NAME_WRONG = 2; //
public TestTomcat(){
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
if(req == null){
return;
}
resp.setContentType("text/html;charset=utf-8");
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
PrintWriter out = resp.getWriter();
String name = req.getParameter("NAME");
String code = req.getParameter("CODE");
/* //浏览器訪问。没传递不论什么參数。用HTML格式给浏览器返回数据
out.println("<html>");
out.println("<head>");
out.println("<title>Tomcat Servlet測试</title>");
out.println("</head>");
out.println("<body>");
out.println("Hello,哥知道你是浏览器訪问的.");
out.println("</body>");
out.println("</html>");
out.println("Hello,第一个Tomcat!!!");
out.close();*/
//手机客户端訪问
int ret = checkSubmit(name, code);
out.print(ret);
out.flush();
out.close();
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
if(req == null){
return;
}
resp.setContentType("text/html;charset=utf-8");
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
PrintWriter out = resp.getWriter();
String name = req.getParameter("NAME");
String code = req.getParameter("CODE");
int ret = checkSubmit(name, code);
out.print(ret);
out.flush();
out.close();
}
/**
* 推断登录名和password
* @param name
* @param code
* @return
*/
private int checkSubmit(String name, String code){
int ret = -2;
if(name.equals("admin")){
if(code.equals("123")){
ret = NAME_CODE_RIGHT;
}else{
ret = CODE_WRONG;
}
}else{
ret = NAME_WRONG;
}
return ret;
}
}
第四步：Android客户端的开发，这里我弄两个button分别相应HttpPost和HttpGet两种方式跟server通讯。
以下是个ScrollView显示server回传结果.效果例如以下所看到的:
watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQveWFuemkxMjI1NjI3/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />
AndroidManifest.xml里加权限: <uses-permission android:name="android.permission.INTERNET"/>
activity_main.xml的内容：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<EditText
android:id="@+id/edit_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="输入username" />
<EditText
android:id="@+id/edit_code"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/edit_name"
android:hint="输入password" />
<LinearLayout
android:id="@+id/layout_btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:orientation="horizontal" >
<Button
android:id="@+id/btn_submit_post"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:text="POST登录 " />
<Button
android:id="@+id/btn_submit_get"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:text="GET登录 " />
</LinearLayout>
<ScrollView
android:id="@+id/info_scroll_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/layout_btn" >
<TextView
android:id="@+id/tv_info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="结果显示........." />
</ScrollView>
</RelativeLayout>MainActivity.java里的内容：
package org.yanzi.testtomecat;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.DefaultClientConnection;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ScrollView;
import android.widget.TextView;
public class MainActivity extends Activity {
public static final String URL = "http://192.168.16.8:8080/TestTomcat/login";
Button submitBtnPost = null;
Button submitBtnGet = null;
TextView infoTextView = null;
EditText nameEdit = null;
EditText codeEdit = null;
ScrollView scrollView = null;
boolean isPost = true; //默认採取post登录方式
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
scrollView = (ScrollView)findViewById(R.id.info_scroll_view);
submitBtnPost = (Button)findViewById(R.id.btn_submit_post);
submitBtnGet = (Button)findViewById(R.id.btn_submit_get);
infoTextView = (TextView)findViewById(R.id.tv_info);
nameEdit = (EditText)findViewById(R.id.edit_name);
codeEdit = (EditText)findViewById(R.id.edit_code);
submitBtnPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
isPost = true;
new SubmitAsyncTask().execute(URL);
}
});
submitBtnGet.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
isPost = false;
new SubmitAsyncTask().execute(URL);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public class SubmitAsyncTask extends AsyncTask<String, Void, String>{
String info = "";
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
String url = params[0];
String reps = "";
if(isPost){
info = "HttpPost返回结果: ";
reps = doPost(url);
}else{
info = "HttpGet返回结果: ";
reps = doGet(url);
}
return reps;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
infoTextView.append("\n" + info + result +"\n");
String res = result.trim();
if(res.equals("0")){
info = "验证通过.....";
}else if(res.equals("1")){
info = "password错误.....";
}else if(res.equals("2")){
info = "username错误.....";
}else if(res.equals("-1")){
info = "返回结果异常！
";
}
infoTextView.append(info + "\n");
scrollView.fullScroll(ScrollView.FOCUS_DOWN);
super.onPostExecute(result);
}
}
private String doGet(String url){
String responseStr = "";
try {
String name = nameEdit.getText().toString().trim();
String code = codeEdit.getText().toString().trim();
String getUrl = URL + "?NAME=" + name+"&"+"CODE=" + code;
HttpGet httpRequest = new HttpGet(getUrl);
HttpParams params = new BasicHttpParams();
ConnManagerParams.setTimeout(params, 1000);
HttpConnectionParams.setConnectionTimeout(params, 3000);
HttpConnectionParams.setSoTimeout(params, 5000);
httpRequest.setParams(params);
HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequest);
final int ret = httpResponse.getStatusLine().getStatusCode();
if(ret == HttpStatus.SC_OK){
responseStr = EntityUtils.toString(httpResponse.getEntity(), HTTP.UTF_8);
}else{
responseStr = "-1";
}
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return responseStr;
}
/**
* 用Post方式跟server传递数据
* @param url
* @return
*/
private String doPost(String url){
String responseStr = "";
try {
HttpPost httpRequest = new HttpPost(url);
HttpParams params = new BasicHttpParams();
ConnManagerParams.setTimeout(params, 1000); //从连接池中获取连接的超时时间
HttpConnectionParams.setConnectionTimeout(params, 3000);//通过网络与server建立连接的超时时间
HttpConnectionParams.setSoTimeout(params, 5000);//读响应数据的超时时间
httpRequest.setParams(params);
//以下開始跟server传递数据，使用BasicNameValuePair
List<BasicNameValuePair> paramsList = new ArrayList<BasicNameValuePair>();
String name = nameEdit.getText().toString().trim();
String code = codeEdit.getText().toString().trim();
paramsList.add(new BasicNameValuePair("NAME", name));
paramsList.add(new BasicNameValuePair("CODE", code));
UrlEncodedFormEntity mUrlEncodeFormEntity = new UrlEncodedFormEntity(paramsList, HTTP.UTF_8);
httpRequest.setEntity(mUrlEncodeFormEntity);
HttpClient httpClient = new DefaultHttpClient();
HttpResponse httpResponse = httpClient.execute(httpRequest);
final int ret = httpResponse.getStatusLine().getStatusCode();
if(ret == HttpStatus.SC_OK){
responseStr = EntityUtils.toString(httpResponse.getEntity(), HTTP.UTF_8);
}else{
responseStr = "-1";
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return responseStr;
}
}
要点凝视：
1、核心在doGet()和doPost()两个函数里，能够看到用get方式比用post传递參数更方便，能够直接写到url里。使用get方式时传递数据在url里写的:
String name = nameEdit.getText().toString().trim();
String code = codeEdit.getText().toString().trim();
String getUrl = URL + "?NAME=" + name+"&"+"CODE=" + code;
post方式时是用BasicNameValuePair来弄的。其它流程都几乎相同。
首先new一个HttpGet或HttpPost，然后设參数。共设三个，作用凝视里有。然后设參数，传数据，通过HttpResponse httpResponse = httpClient.execute(httpRequest);得到返回结果。
2、假设在Tomcat里使用的是out.println()，则再解析数据时须要再得到的String上trim()一下，否则会错。
3、Android客户端URL地址为:
public static final String URL = "http://192.168.16.8:8080/TestTomcat/login";
这里的IP就是电脑的IP加端口号就ok。
当然这仅是个最主要的演示样例，遗留问题：
1.JSON传递数据
2.每次链接都开一个DefaultHttpClient非常不科学。
參考: