HttpClient的基础应用

HttpClient是用来发送HTTP请求的，也就是HTTP的客户端。任何HTTP请求都可以由它模拟出来。

 

1.发送GET请求：

                HttpClient httpClient = new DefaultHttpClient();
                // 初始化GET请求
                HttpGet get = new HttpGet("http://localhost:8080");
                // 执行GET请求
                HttpResponse response = httpClient.execute(get);
                // 获取请求返回的数据
		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;
			}
			System.out.println(new String(all));
			in.close();
		}
                // 一次GET请求结束
		get.abort();

 

2.发送POST请求

HttpClient httpClient = new DefaultHttpClient();
HttpPost get = new HttpPost("http://localhost:8080/xxxxxx");
//创建表单参数列表  
List<NameValuePair> qparams = new ArrayList<NameValuePair>(); 
// 添加参数
qparams.add(new BasicNameValuePair("id", "5"));
//填充表单  
get.setEntity(new UrlEncodedFormEntity(qparams,"UTF-8"));
// 执行POST请求
HttpResponse response = httpClient.execute(get);
HttpEntity entity = response.getEntity();
// ......
// 接下来就与GET一样了

 

3.自己封装请求的输入流

HttpClient httpClient = new DefaultHttpClient();
// 封装输入流
ContentProducer cp = new ContentProducer() {
	public void writeTo(OutputStream outstream) throws IOException {
		Writer writer = new OutputStreamWriter(outstream, "UTF-8");
		writer.write("write the stream by myself");
		writer.flush();
	}
};
HttpEntity requestEntity = new EntityTemplate(cp);
HttpPost httppost = new HttpPost("http://localhost:8080/xxx");
httppost.setEntity(requestEntity);
HttpResponse response = httpClient.execute(httppost);
HttpEntity entity = response.getEntity();
// 接下来与GET/POST一样了。