我最近尝试了从square的Retrofit Library，它很棒，你可以很容易地调用你的rest API。 基于注释的配置使我们摆脱了大量的锅炉板编码。

我写了一个库，将java接口映射到远程JSON REST服务:

https://github.com/ggeorgovassilis/spring-rest-invoker

public interface BookService {
   @RequestMapping("/volumes")
   QueryResult findBooksByTitle(@RequestParam("q") String q);

   @RequestMapping("/volumes/{id}")
   Item findBookById(@PathVariable("id") String id);
}

这是一个老问题(2008年)，所以现在的选择比当时多得多:

Apache CXF有三个不同的REST客户端选项 泽西岛(上面提到过)。 Spring RestTemplate被Spring WebClient取代 公共HTTP客户端为旧的Java项目构建自己的。

更新(2020年仍然活跃的项目):

Apache HTTP Components (4.2) Fluent adapter - Basic replacement for JDK, used by several other candidates in this list. Better than old Commons HTTP Client 3 and easier to use for building your own REST client. You'll have to use something like Jackson for JSON parsing support and you can use HTTP components URIBuilder to construct resource URIs similar to Jersey/JAX-RS Rest client. HTTP components also supports NIO but I doubt you will get better performance than BIO given the short requestnature of REST. Apache HttpComponents 5 has HTTP/2 support. OkHttp - Basic replacement for JDK, similar to http components, used by several other candidates in this list. Supports newer HTTP protocols (SPDY and HTTP2). Works on Android. Unfortunately it does not offer a true reactor-loop based async option (see Ning and HTTP components above). However if you use the newer HTTP2 protocol this is less of a problem (assuming connection count is problem). Ning Async-http-client - provides NIO support. Previously known as Async-http-client by Sonatype. Feign wrapper for lower level http clients (okhttp, apache httpcomponents). Auto-creates clients based on interface stubs similar to some Jersey and CXF extensions. Strong spring integration. Retrofit - wrapper for lower level http clients (okhttp). Auto-creates clients based on interface stubs similar to some Jersey and CXF extensions. Volley wrapper for jdk http client, by google google-http wrapper for jdk http client, or apache httpcomponents, by google Unirest wrapper for jdk http client, by kong Resteasy JakartaEE wrapper for jdk http client, by jboss, part of jboss framework jcabi-http wrapper for apache httpcomponents, part of jcabi collection restlet wrapper for apache httpcomponents, part of restlet framework rest-assured wrapper with asserts for easy testing

关于选择HTTP/REST客户端的一个警告。确保检查你的框架栈为HTTP客户端使用了什么，它是如何执行线程的，如果它提供了一个客户端，最好使用相同的客户端。这是如果你使用像Vert。你可能想尝试使用它的后台客户端来参与框架提供的任何总线或反应器循环…否则，请为可能出现的有趣的线程问题做好准备。

我使用Apache HTTPClient来处理所有HTTP方面的事情。

我为XML内容编写XML SAX解析器，用于将XML解析为对象模型。我认为Axis2还公开了XML -> Model方法(Axis 1隐藏了这一部分，令人恼火)。XML生成器非常简单。

在我看来，它不需要很长时间来编码，而且非常高效。

我目前正在使用https://github.com/kevinsawicki/http-request，我喜欢他们的简单性和展示示例的方式，但当我阅读时，我主要是被卖了:

依赖关系是什么? 一个也没有。这个库的目标是成为带有一些内部静态类的单个类。测试项目确实需要Jetty，以便根据实际的HTTP服务器实现测试请求。

这解决了Java 1.6项目中的一些问题。至于把json解码成对象，gson是无敌的:)

泽西休息客户端的例子

添加依赖项:

<!-- Jersey -->
<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-json</artifactId>
    <version>1.8</version>
</dependency>

<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-server</artifactId>
    <version>1.8</version>
</dependency>
    
<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-client</artifactId>
    <version>1.8</version>
</dependency>

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20090211</version>
</dependency>

对于GetMethod，并传递两个参数:

Client client = Client.create();
WebResource webResource1 = client
                        .resource("http://localhost:10102/NewsTickerServices/AddGroup/"
                                + userN + "/" + groupName);

ClientResponse response1 = webResource1.get(ClientResponse.class);
System.out.println("responser is" + response1);

GetMethod传递一个参数并获得一个List类型的响应:

Client client = Client.create();
 
WebResource webResource1 = client
                    .resource("http://localhost:10102/NewsTickerServices/GetAssignedUser/"+grpName);    
//value changed
String response1 = webResource1.type(MediaType.APPLICATION_JSON).get(String.class);
 
List <String > Assignedlist = new ArrayList<String>();
JSONArray jsonArr2 = new JSONArray(response1);
for (int i =0;i<jsonArr2.length();i++){
        
    Assignedlist.add(jsonArr2.getString(i));    
}

上面它返回一个列表，我们将其作为list对象接受，然后将其转换为JSONArray，然后从JSONArray转换为list。

Post请求传递JSONObject作为参数:

Client client = Client.create();
WebResource webResource = client
            .resource("http://localhost:10102/NewsTickerServices/CreateJUser");
// value added

ClientResponse response = webResource.type(MediaType.APPLICATION_JSON).post(ClientResponse.class, mapper.writeValueAsString(user));

if (response.getStatus() == 500) {

    context.addMessage(null, new FacesMessage("User already exist "));
}