在几行java代码中读取url to string

Question

我试图找到Java相当于Groovy的:

String content = "http://www.google.com".toURL().getText();

我想将URL中的内容读入字符串.我不想用缓冲的流和循环来污染我的代码以完成这么简单的任务.我查看了apache的HttpClient,但我也没有看到一行或两行实现.

Answer 1

既然原来的答案被接受了一段时间,那么有一个更好的方法:

String out = new Scanner(new URL("http://www.google.com").openStream(), "UTF-8").useDelimiter("\\A").next();

如果您想要一个稍微全面的实现,这不是一行,请执行以下操作:

public static String readStringFromURL(String requestURL) throws IOException
{
    try (Scanner scanner = new Scanner(new URL(requestURL).openStream(),
            StandardCharsets.UTF_8.toString()))
    {
        scanner.useDelimiter("\\A");
        return scanner.hasNext() ? scanner.next() : "";
    }
}

Answer 2

这个答案指的是Java的旧版本.你可能想看一下ccleve的答案.

以下是执行此操作的传统方法:

import java.net.*;
import java.io.*;

public class URLConnectionReader {
    public static String getText(String url) throws Exception {
        URL website = new URL(url);
        URLConnection connection = website.openConnection();
        BufferedReader in = new BufferedReader(
                                new InputStreamReader(
                                    connection.getInputStream()));

        StringBuilder response = new StringBuilder();
        String inputLine;

        while ((inputLine = in.readLine()) != null) 
            response.append(inputLine);

        in.close();

        return response.toString();
    }

    public static void main(String[] args) throws Exception {
        String content = URLConnectionReader.getText(args[0]);
        System.out.println(content);
    }
}

正如@extraneon所建议的那样,ioutils允许你以一种非常雄辩的方式做到这一点,这仍然是Java精神:

 InputStream in = new URL( "http://jakarta.apache.org" ).openStream();

 try {
   System.out.println( IOUtils.toString( in ) );
 } finally {
   IOUtils.closeQuietly(in);
 }

Answer 3

或者只是使用IOUtils.toString(URL url),或者也接受编码参数的变体.

Answer 4

现在已经过了更多时间,这是在Java 8中实现它的一种方法:

URLConnection conn = url.openConnection();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
    pageText = reader.lines().collect(Collectors.joining("\n"));
}

Answer 5

从Java 9开始,还有一种更好的方法:

URL u = new URL("http://www.example.com/");
try (InputStream in = u.openStream()) {
    return new String(in.readAllBytes(), StandardCharsets.UTF_8);
}

与原始的groovy示例一样,这假定内容是UTF-8编码的.(如果你需要比这更聪明的东西,你需要创建一个URLConnection并用它来计算编码.)

Answer 6

使用Guava的其他示例:

URL xmlData = ...
String data = Resources.toString(xmlData, Charsets.UTF_8);

Answer 7

Java 11+：

URI uri = URI.create("http://www.google.com");
HttpRequest request = HttpRequest.newBuilder(uri).build();
String content = HttpClient.newHttpClient().send(request, BodyHandlers.ofString()).body();