如何使用Java编写一个RESTful客户端

如果你需要在Java中使用RESTful API，那么你需要编写一个RESTful客户端。在这篇文章中，我将介绍如何使用Java编写一个RESTful客户端。

首先，我们需要使用Java的HTTP客户端库。有很多可供选择的库，比如Apache HttpComponents、OkHttp等。在这里，我将使用Apache HttpComponents。

创建一个名为RestfulClient.java的文件，添加以下代码：

import java.io.BufferedReader;

import java.io.InputStreamReader;

import org.apache.http.HttpResponse;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;

public class RestfulClient {

public static void main(String[] args) throws Exception {

    String url = "http://example.com/api/users";

    DefaultHttpClient httpClient = new DefaultHttpClient();
    HttpGet getRequest = new HttpGet(url);

    getRequest.addHeader("accept", "application/json");

    HttpResponse response = httpClient.execute(getRequest);

    if (response.getStatusLine().getStatusCode() != 200) {
        throw new RuntimeException("Failed : HTTP error code : "
           + response.getStatusLine().getStatusCode());
    }

    BufferedReader br = new BufferedReader(
                     new InputStreamReader((response.getEntity().getContent())));

    String output;
    System.out.println("Output from Server .... \n");
    while ((output = br.readLine()) != null) {
        System.out.println(output);
    }

    httpClient.getConnectionManager().shutdown();

}

}