我正在尝试使用 Java 客户端调用 REST API。
其余 API https://api.gdc.cancer.gov/data有文件数据。 当我将文件名附加到 URL ( https://api.gdc.cancer.gov/data/556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c ) 时,我可以使用浏览器下载给定的文件。
这里的文件名是 556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c
。
你能告诉我吗,我怎样才能在这个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 + "] } } }";
}
}
最佳答案
您不能只输出一个字符串,因为您正在尝试下载 pdf。如果您只想下载文件,则有一种更简单的方法改编自 this回答:
String requestUrl = "https://api.gdc.cancer.gov/data/556e5e3f-0ab9-4b6c-aa62-c42f6a6cf20c";
URL url = new URL(requestUrl);
InputStream in = url.openStream();
Files.copy(in, Paths.get("your_filename.pdf"), StandardCopyOption.REPLACE_EXISTING);
in.close();
System.out.println("finished!");
我已经针对您提供的 URL 对其进行了测试,并毫无问题地获得了 pdf 文件。
关于java - 使用 REST API 下载文件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/51629661/