一、HttpClient

(一)HttpClient 客户端

1、HttpClient 是 apache 的开源，需要引入两个包：httpclient-4.2.4.jar 和 httpcore-4.2.2.jar。

/**

* HttpClien 的客户端访问

*/

private void httpClientVisit() {

String clientResponse = "";

try {

HttpClient client = new DefaultHttpClient();

HttpPost request = new HttpPost(mUrl);

//不是表单数据提交，这边使用 StringEntity 即可

//UrlEncodedFormEntity等都是 HttpEntity 接口的实现类

StringEntity entity = new StringEntity(mRequestXml, "UTF-8");//编码

entity.setContentType("text/xml");

request.setEntity(entity);

// 发送请求

HttpResponse response = client.execute(request);

org.apache.http.HttpEntity httpEntity = response.getEntity();

if (httpEntity != null) {

// EntityUtils.toString 如果不指定编码，EntityUtils默认会使用ISO_8859_1进行编码

clientResponse = EntityUtils.toString(httpEntity, "UTF-8");// 记得设置编码或者如下

// clientResponse = new String(EntityUtils.toString(httpEntity).getBytes("ISO_8859_1"), "UTF-8");

}

if (clientResponse == null || "".equals(clientResponse)) {

System.err.println("clientResponse is null or empty.");

}

System.out.println(clientResponse);

} catch (Exception e) {

e.printStackTrace();

}

}

(二)HttpClient 详解

1、Post方式访问

/**

* post方式提交表单(模拟用户登录请求)

*/

public void postForm() {

String url = "http://localhost:8080/Java_WS_Server/rest/surpolicy/sendXml";

// 创建默认的httpClient实例.

HttpClient client = new DefaultHttpClient();

// 创建httppost

HttpPost httppost = new HttpPost(url);

// 创建参数队列

List formparams = new ArrayList();

formparams.add(new BasicNameValuePair("username", "admin"));

formparams.add(new BasicNameValuePair("password", "123456"));

UrlEncodedFormEntity uefEntity;

try {

uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); //编码

httppost.setEntity(uefEntity);

System.out.println("executing request " + httppost.getURI());

HttpResponse response = client.execute(httppost);

Header[] headers = response.getAllHeaders();

for(int i=0; i

System.out.println(headers[i].getName());

}

try {

HttpEntity entity = response.getEntity();

if (entity != null) {

System.out.println("--------------------------------------");

System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8")); //编码

System.out.println("--------------------------------------");

}

} finally {

}

} catch (ClientProtocolException e) {

e.printStackTrace();

} catch (UnsupportedEncodingException e1) {

e1.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

} finally {

}

}

2、Get方式访问

/**

* 发送 get请求

*/

public void get() {

try {

HttpClient client = new DefaultHttpClient();

// 创建httpget.

HttpGet httpget = new HttpGet("http://www.baidu.com/");

System.out.println("executing request " + httpget.getURI());

// 执行get请求.

HttpResponse response = client.execute(httpget);

try {

// 获取响应实体

HttpEntity entity = response.getEntity();

System.out.println("--------------------------------------");

// 打印响应状态

System.out.println(response.getStatusLine());

if (entity != null) {

// 打印响应内容长度

System.out.println("Response content length: " + entity.getContentLength());

// 打印响应内容

System.out.println("Response content: " + EntityUtils.toString(entity));

}

System.out.println("------------------------------------");

} finally {

}

} catch (ClientProtocolException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

} finally {}

}

3、乱码问题：

1)利用：UrlEncodedFormEntity等 entity 容器，实现发送内容的编码：

UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); //编码

StringEntity entity = new StringEntity(mRequestXml, "UTF-8");//编码

2、EntityUtils.toString()方法的转码，实现返回内容的编码：

EntityUtils.toString 如果不指定编码，EntityUtils默认会使用ISO_8859_1进行编码

clientResponse = EntityUtils.toString(httpEntity, "UTF-8");// 记得设置编码或者如下

clientResponse = new String(EntityUtils.toString(httpEntity).getBytes("ISO_8859_1"), "UTF-8");

二、RestTemplate

(一)RestTemplate 客户端

1、RestTemplate 是Spring的封装，需要spring的包 spring-web-3.0.7.RELEASE.jar

2、客户端代码：

/**

* RestTemplate 客户端访问

*/

private void RestTemplateVisit() {

String returnXml = ""; // 核心返回结果报文字符串

try {

//复杂构造函数的使用

SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();

requestFactory.setConnectTimeout(1000);// 设置超时

requestFactory.setReadTimeout(1000);

//利用复杂构造器可以实现超时设置，内部实际实现为 HttpClient

RestTemplate restTemplate = new RestTemplate(requestFactory);

//设置HTTP请求头信息，实现编码等

HttpHeaders requestHeaders = new HttpHeaders();

// requestHeaders.set("Accept", "text/");

requestHeaders.set("Accept-Charset", "utf-8");

requestHeaders.set("Content-type", "text/xml; charset=utf-8");// 设置编码

//利用容器实现数据封装，发送

HttpEntity entity = new HttpEntity(mRequestXml, requestHeaders);

returnXml = restTemplate.postForObject(mUrl, entity, String.class);

// 转码原因：RestTemplate默认是使用org.springframework.http.converter.StringHttpMessageConverter来解析

// StringHttpMessageConverter 默认用的 ISO-8859-1来编码的

returnXml = new String(returnXml.getBytes("ISO-8859-1"), "utf-8");

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

}

System.out.println("restTemplate客户端访问返回： \n" + returnXml);

}

具体的参考这个博客：

http://blog.csdn.net/u012228718/article/details/42028951