HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了,越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。虽然在 JDK 的 java net包中已经提供了访问 HTTP 协议的基本功能,但是对于大部分应用程序来说,JDK 库本身提供的功能还不够丰富和灵活。HttpClient 是 Apache Jakarta Common 下的子项目,用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议。HttpClient 已经应用在很多的项目中,比如 Apache Jakarta 上很著名的另外两个开源项目 Cactus 和 HTMLUnit 都使用了 HttpClient。
以下列出的是 HttpClient 提供的主要的功能,要知道更多详细的功能可以参见 HttpClient 的主页。
(1)实现了所有 HTTP 的方法(GET,POST,PUT,HEAD 等)
(2)支持自动转向
(3)支持 HTTPS 协议
(4)支持代理
服务器等
下载地址:
测试案例:
1.通过GET方法执行请求
@Test
public void doGet() throws Exception {
//创建一个httpclient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
//创建一个GET对象
HttpGet get = new HttpGet("http://www.sogou.com");
//执行请求
CloseableHttpResponse response = httpClient.execute(get);
//取响应的结果
int statusCode = response.getStatusLine().getStatusCode();
System.out.println(statusCode);
HttpEntity entity = response.getEntity();
String string = EntityUtils.toString(entity, "utf-8");
System.out.println(string);
//关闭httpclient
response.close();
httpClient.close();
}
2.通过GET方法带参数执行请求
@Test
public void doGetWithParam() throws Exception{
//创建一个httpclient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
//创建一个uri对象
URIBuilder uriBuilder = new URIBuilder("http://www.sogou.com/web");
uriBuilder.addParameter("query", "花千骨");
HttpGet get = new HttpGet(uriBuilder.build());
//执行请求
CloseableHttpResponse response = httpClient.execute(get);
//取响应的结果
int statusCode = response.getStatusLine().getStatusCode();
System.out.println(statusCode);
HttpEntity entity = response.getEntity();
String string = EntityUtils.toString(entity, "utf-8");
System.out.println(string);
//关闭httpclient
response.close();
httpClient.close();
}
3.使用httpclient执行post请求
@Test
public void doPost() throws Exception {
CloseableHttpClient httpClient = HttpClients.createDefault();
//创建一个post对象
HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.html");
//执行post请求
CloseableHttpResponse response = httpClient.execute(post);
String string = EntityUtils.toString(response.getEntity());
System.out.println(string);
response.close();
httpClient.close();
}
4.带参数的post请求
@RequestMapping(value="/http/post",method=RequestMethod.POST)
@ResponseBody
public String postTest(String name,String password) {
return "name:"+name+"/password"+password;
}
@Test
public void doPostWithParam() throws Exception{
CloseableHttpClient httpClient = HttpClients.createDefault();
//创建一个post对象
HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.html");
//创建一个Entity。模拟一个表单
List<NameValuePair> kvList = new ArrayList<>();
kvList.add(new BasicNameValuePair("username", "zhangsan"));
kvList.add(new BasicNameValuePair("password", "123"));
//包装成一个Entity对象
StringEntity entity = new UrlEncodedFormEntity(kvList, "utf-8");
//设置请求的内容
post.setEntity(entity);
//执行post请求
CloseableHttpResponse response = httpClient.execute(post);
String string = EntityUtils.toString(response.getEntity());
System.out.println(string);
response.close();
httpClient.close();
}