一、HttpClient介绍
HttpClient是用来模拟HTTP请求的，其实实质就是把HTTP请求模拟后发给Web服务器；
Android已经集成了HttpClient，因此可以直接使用；
注：此处HttpClient代码不只可以适用于Android，也可适用于一般的Java程序；
HTTP GET核心代码：
(1)DefaultHttpClient client = new DefaultHttpClient();
(2)HttpGet get = new HttpGet(String url);//此处的URL为http://..../path?arg1=value&....argn=value
(3)HttpResponse response = client.execute(get); //模拟请求
(4)int code = response.getStatusLine().getStatusCode();//返回响应码
(5)InputStream in = response.getEntity().getContent();//服务器返回的数据
HTTP POST核心代码：
(1)DefaultHttpClient client = new DefaultHttpClient();
(2)BasicNameValuePair pair = new BasicNameValuePair(String name,String value);//创建一个请求头的字段，比如content-type,text/plain
(3)UrlEncodedFormEntity entity = new UrlEncodedFormEntity(List<NameValuePair> list,String encoding);//对自定义请求头进行URL编码
(4)HttpPost post = new HttpPost(String url);//此处的URL为http://..../path
(5)post.setEntity(entity);
(6)HttpResponse response = client.execute(post);
(7)int code = response.getStatusLine().getStatusCode(); //返回响应码
(8)InputStream in = response.getEntity().getContent();//服务器返回的数据
在AndroidManifest.xml加入：
< uses-permission android:name="android.permission.INTERNET"/>
二、服务器端代码
服务器端代码和通过URLConnection发出请求的代码不变：
package org.xiazdong.servlet; import java.io.IOException; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/Servlet1") public class Servlet1 extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String nameParameter = request.getParameter("name"); String ageParameter = request.getParameter("age"); String name = new String(nameParameter.getBytes("ISO-8859-1"),"UTF-8"); String age = new String(ageParameter.getBytes("ISO-8859-1"),"UTF-8"); System.out.println("GET"); System.out.println("name="+name); System.out.println("age="+age); response.setCharacterEncoding("UTF-8"); OutputStream out = response.getOutputStream();//返回数据 out.write("GET请求成功!".getBytes("UTF-8")); out.close(); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); String name = request.getParameter("name"); String age = request.getParameter("age"); System.out.println("POST"); System.out.println("name="+name); System.out.println("age="+age); response.setCharacterEncoding("UTF-8"); OutputStream out = response.getOutputStream(); out.write("POST请求成功!".getBytes("UTF-8")); out.close(); } }
三、Android客户端代码
效果如下：
在AndroidManifest.xml加入：
[html] < uses-permission android:name="android.permission.INTERNET"/>
MainActivity.java
[java] package org.xiazdong.network.httpclient; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.URLEncoder; import java.util.ArrayList; import java.util.List; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; 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.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.Toast;
public class MainActivity extends Activity {
private EditText name, age;
private Button getbutton, postbutton;
private OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
try{
if(postbutton==v){
/* * NameValuePair代表一个HEADER，List<NameValuePair>存储全部的头字段 * UrlEncodedFormEntity类似于URLEncoder语句进行URL编码 * HttpPost类似于HTTP的POST请求 * client.execute()类似于发出请求，并返回Response */
DefaultHttpClient client = new DefaultHttpClient();
List<NameValuePair> list = new ArrayList<NameValuePair>();
NameValuePair pair1 = new BasicNameValuePair("name", name.getText().toString());
NameValuePair pair2 = new BasicNameValuePair("age", age.getText().toString());
list.add(pair1);
list.add(pair2);
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list,"UTF-8");
HttpPost post = new HttpPost("http://192.168.0.103:8080/Server/Servlet1");
post.setEntity(entity);
HttpResponse response = client.execute(post);
if(response.getStatusLine().getStatusCode()==200){
InputStream in = response.getEntity().getContent();//接收服务器的数据，并在Toast上显示
String str = readString(in);
Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
}
else Toast.makeText(MainActivity.this, "POST提交失败", Toast.LENGTH_SHORT).show();
}
if(getbutton==v){
DefaultHttpClient client = new DefaultHttpClient();
StringBuilder buf = new StringBuilder("http://192.168.0.103:8080/Server/Servlet1");
buf.append("?");
buf.append("name="+URLEncoder.encode(name.getText().toString(),"UTF-8")+"&");
buf.append("age="+URLEncoder.encode(age.getText().toString(),"UTF-8"));
HttpGet get = new HttpGet(buf.toString());
HttpResponse response = client.execute(get);
if(response.getStatusLine().getStatusCode()==200){
InputStream in = response.getEntity().getContent();
String str = readString(in);
Toast.makeText(MainActivity.this, str, Toast.LENGTH_SHORT).show();
}
else Toast.makeText(MainActivity.this, "GET提交失败", Toast.LENGTH_SHORT).show();
}
}
catch(Exception e){}
}
};
@Override
public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); name = (EditText) this.findViewById(R.id.name); age = (EditText) this.findViewById(R.id.age); getbutton = (Button) this.findViewById(R.id.getbutton); postbutton = (Button) this.findViewById(R.id.postbutton); getbutton.setOnClickListener(listener); postbutton.setOnClickListener(listener); } protected String readString(InputStream in) throws Exception { byte[]data = new byte[1024]; int length = 0; ByteArrayOutputStream bout = new ByteArrayOutputStream(); while((length=in.read(data))!=-1){ bout.write(data,0,length); } return new String(bout.toByteArray(),"UTF-8"); } }