使用 RestTemplate 进行基本身份验证 - 编译错误 - 构造函数 HttpClient() 不可见答案

【问题标题】：Basic Authentication with RestTemplate - compilation error - The constructor HttpClient() is not visible使用 RestTemplate 进行基本身份验证 - 编译错误 - 构造函数 HttpClient() 不可见
【发布时间】：2013-03-05 22:07:41
【问题描述】：

尝试将基本身份验证添加到 restTemplate

我遇到的问题是我无法初始化：（代码 sn-p 中的两个导入）

HttpClient client = new HttpClient();

此代码在编译错误中解决（eclipse 没有提供解决此问题的建议）

1) 有什么问题？

2) 我是否导入了错误的类？

我的代码 sn-p：

import org.apache.http.client.HttpClient;
//OR (not together)
import sun.net.www.http.HttpClient;


HttpClient client = new HttpClient(); //this line dosent compile
UsernamePasswordCredentials credentials =
new UsernamePasswordCredentials("USERNAME","PASS");
client.getState().setCredentials(
  new AuthScope("www.example.com", 9090, AuthScope.ANY_REALM),
  credentials);
CommonsClientHttpRequestFactory commons =
     new CommonsClientHttpRequestFactory(client);

RestTemplate template = new RestTemplate(commons);
SomeObject result = template.getForObject(
     "http://www.example.com:9090/",SomeObject.class
 );

运行这个得到异常：

> failed due to an unhandled exception: java.lang.Error: Unresolved
> compilation problems:     The constructor HttpClient() is not visible
>   The method getState() is undefined for the type HttpClient
>   CommonsClientHttpRequestFactory cannot be resolved to a type
>   CommonsClientHttpRequestFactory cannot be resolved to a type
>   SomeObject cannot be resolved to a type     The method
> getForObject(String, Class<SomeObject>, Object...) from the type
> RestTemplate refers to the missing type SomeObject    SomeObject cannot
> be resolved to a type

【问题讨论】：

标签： java spring rest http-headers basic-authentication

【解决方案1】：

最终，使用以下方式运行基本身份验证要容易得多：

restTemplate.exchange()

而不是

restTemplate.getForObject()

我的代码 sn-p：

private HttpHeaders createHeaders(final String username, final String password ){
    HttpHeaders headers =  new HttpHeaders(){
          {
             String auth = username + ":" + password;
             byte[] encodedAuth = Base64.encodeBase64(
                auth.getBytes(Charset.forName("US-ASCII")) );
             String authHeader = "Basic " + new String( encodedAuth );
             set( "Authorization", authHeader );
          }
       };
       headers.add("Content-Type", "application/xml");
       headers.add("Accept", "application/xml");

       return headers;
}


    RestTemplate restTemplate = new RestTemplate();
    ResponseEntity<MyClass> response;
    httpHeaders = this.createHeaders("user", "pass");

    String url = "www.example.com"
    response = restTemplate.exchange(url, HttpMethod.GET, new HttpEntity<Object>(httpHeaders), MyClass.class);

它有效！

【讨论】：

【解决方案2】：

如果你使用Apache HttpClient，实例化DefaultHttpClient，因为HttpClient只是一个接口：

HttpClient httpclient = new DefaultHttpClient();

请参阅有关使用HttpClient here 的各种身份验证方案的文档。

【讨论】：

当使用这个选项时我无法唤起：client.getState()
那是因为它没有这个方法。尝试this example 进行客户端身份验证。
或者this example 更好，因为它会将凭据预先发送到服务器。

【解决方案3】：

我们可以通过以下方式在 Spring boot 中使用它：

   @SpringBootApplication

公共类应用程序实现 CommandLineRunner{

private static final Logger log = LoggerFactory.getLogger(Application.class);

public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
}

@Override
public void run(String... args) throws Exception {
    try{
    RestTemplate restTemplate = new RestTemplate();
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders = this.createHeaders();
    ResponseEntity<String> response;
    response  = restTemplate.exchange("<url>",HttpMethod.GET,new HttpEntity<Object>(httpHeaders),String.class);
    log.info(response.toString());
    }
    catch(Exception e)
    {
        System.out.println("Exception"+e);
    }


}

private HttpHeaders createHeaders(){
    HttpHeaders headers =  new HttpHeaders(){
          {            
             set( "Authorization", "3ee140");
          }
       };

       return headers;
}

}

【讨论】：