使用HttpClient发送http请求，并解析从服务器端返回的数据

使用Apache的httpclient包可以模拟HTTP请求的发送， get和post均可以。最方便的地方就是请求struts等web框架进行测试，省去了做测试页面的差事。

[java]
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import
java.io.IOException;

import
java.io.InputStream;

import
java.util.ArrayList;

import
java.util.List;

import
java.util.Map;

import
java.util.Set;

import
org.apache.http.HttpEntity;

import
org.apache.http.HttpResponse;

import
org.apache.http.NameValuePair;

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.entity.BufferedHttpEntity;

import
org.apache.http.impl.client.DefaultHttpClient;

import
org.apache.http.message.BasicNameValuePair;

public
class
Client {

public
String sendGet(String url) throws
ClientProtocolException, IOException{

String result =

null;

HttpClient httpClient =

new DefaultHttpClient();

HttpGet get =

new HttpGet(url);

InputStream in =

null;

try
{

HttpResponse response = httpClient.execute(get);

HttpEntity entity = response.getEntity();

if
(entity != null)
{

entity =

new BufferedHttpEntity(entity);

in = entity.getContent();

byte[]
read = new
byte[1024];

byte[]
all = new
byte[0];

int
num;

while
((num = in.read(read)) > 0)
{

byte[]
temp = new
byte[all.length
+ num];

System.arraycopy(all,

0, temp,
0,
all.length);

System.arraycopy(read,

0, temp, all.length, num);

all = temp;

}

result =

new String(all,
"UTF-8");

}

}

finally {

if
(in != null)
in.close();

get.abort();

}

return
result;

}

public
String sendPost(String url, Map<String, String> params) throws
ClientProtocolException, IOException{

String result =

null;

HttpClient httpClient =

new DefaultHttpClient();

HttpPost get =

new HttpPost(url);

//
创建表单参数列表

List<NameValuePair> qparams =

new ArrayList<NameValuePair>();

Set<String> keys = params.keySet();

for
(String key : keys) {

qparams.add(new
BasicNameValuePair(key, params.get(key)));

}

//
填充表单

get.setEntity(new
UrlEncodedFormEntity(qparams,"UTF-8"));

HttpResponse response = httpClient.execute(get);

HttpEntity entity = response.getEntity();

if
(entity != null)
{

entity =

new BufferedHttpEntity(entity);

InputStream in = entity.getContent();

byte[]
read = new
byte[1024];

byte[]
all = new
byte[0];

int
num;

while
((num = in.read(read)) > 0)
{

byte[]
temp = new
byte[all.length
+ num];

System.arraycopy(all,

0, temp,
0,
all.length);

System.arraycopy(read,

0, temp, all.length, num);

all = temp;

}

result =

new String(all,"UTF-8");

if
(null
!= in) {

in.close();

}

}

get.abort();

return
result;

}

public
String sendGet(String url, Map<String, String> params) throws
ClientProtocolException, IOException {

Set<String> keys = params.keySet();

StringBuilder urlBuilder =

new StringBuilder(url +
"?");

for
(String key : keys) {

urlBuilder.append(key).append("=").append(params.get(key)).append("&");

}

urlBuilder.delete(urlBuilder.length() -

1, urlBuilder.length());

return
this.sendGet(urlBuilder.toString());

}

}

如果服务器返回的是XML，上面的方法返回的就是xml的字符串，如"<XML><student>......</student></XML>"。在处理xml非常管用。

上面的例子，如果使用第二种或者第三种方法，需要将参数放在Map<String, String>中