Question

我正在尝试使用Java客户端调用REST API。

Rest API https://api.gdc.cancer.gov/data具有文件数据。将文件名附加到URL（https://api.gdc.cancer.gov/data/556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c）后，可以使用浏览器下载给定文件。

此处文件名是556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c。

请让我知道，我如何在这个JAVA中实现。我正在使用的代码。

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class DownloadFilesAPI {
    public DownloadFilesAPI() {
        super();
    }

    public static String sendPostRequest(String requestUrl) {
        StringBuffer jsonString = new StringBuffer();
        try {
            URL url = new URL(requestUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            // connection.setRequestMethod("POST");
            //   connection.connect();
            //Get the response status of the Rest API
            //  int responsecode = connection.getResponseCode();
            //System.out.println("Response code is: " +responsecode);
            //connection.getResponseMessage();
            // System.out.println(connection.getResponseMessage());

            connection.setDoInput(true);
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Accept", "application/json");
            connection.setRequestProperty("Content-Type", "application/json");
            //  System.out.println(connection.getResponseMessage());
            //  System.out.println( JsonPath.from(requestUrl));
            OutputStreamWriter writer = new 
            OutputStreamWriter(connection.getOutputStream());
            writer.write(requestUrl);
            writer.close(); 
            /* BufferedReader br = new BufferedReader(new 
            InputStreamReader(connection.getInputStream()));

            String line;
            while ((line = br.readLine()) != null) {
                jsonString.append(line);
            }
            br.close(); */
            connection.disconnect();
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage());
        }
        return jsonString.toString();
    }

    public static void main(String[] args) {
        List<String> values = new ArrayList<>();
        // values.add("556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c");
        String requestUrl = "https://api.gdc.cancer.gov/data/556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c";
        sendPostRequest(requestUrl);
    }
    private static String preparePayload(List<String> values) {
    StringBuilder sb = new StringBuilder();
    for (String value : values) {
        sb.append("\"" + value + "\",");
    }
    String Requiredvalue = sb.toString().substring(0, sb.toString().length() - 1);
    return "{ \"ids\":[" + Requiredvalue + "] } } }";
    } 
}

Answer 1

由于您正在尝试下载pdf文件，因此无法仅输出字符串。如果您只想下载文件，则可以使用一种更简单的方法来改编this答案：

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form name="CheckOn" >
<table id="tblID" BORDER="1">
<tr class="heading">
  <td>Items</td>
  <td>Default value</td>
  <td>Extra(if any)</td>
  <td>Output</td>
 </tr>
 <tr>
    <td>Apple</td>
    <td>
      <input type="text" value="26" size=15 name="apple">
    </td>
    <td>
      <input type="text" value="0" size=15 name="apple">
    </td>
	<td>
      <input type="text" size=15 name="apple">
    </td>
  </tr>
   <tr>
    <td>Mango</td>
    <td><input type="text" size=15 value="26" name="SDK"></td>
    <td>
      <input type="text" value="0" size=15 name="SDK">
    </td>
	<td>
      <input type="text" size=15 name="SDK">
    </td>
  </tr>
  <tr>
    <td>Banana</td>
    <td>
      <input type="text" value="26" size=15 name="Banana">
    </td>
    <td>
      <input type="text" value="27" size=15 name="Banana">
    </td>
	<td>
      <input type="text" size=15 name="Banana">
    </td>
  </tr>
  <tr>
</table>
<p><input type="submit" value="submit" id="subs" name="subs"></p>

我已经对您提供的URL进行了测试，并获得了pdf文件，没有任何问题。

使用REST API下载文件

1 个答案: