在Java中组合URL或URI的惯用方法是什么？

Question

如何在Java中构建URL或URI？是否有惯用的方式,或者很容易做到这一点的库？

我需要允许从请求字符串开始,解析/更改各种URL部分(方案,主机,路径,查询字符串)并支持添加和自动编码查询参数.

Answer 1

从Apache HTTP Component HttpClient 4.1.3开始,来自官方教程:

public class HttpClientTest {
public static void main(String[] args) throws URISyntaxException {
    List<NameValuePair> qparams = new ArrayList<NameValuePair>();
    qparams.add(new BasicNameValuePair("q", "httpclient"));
    qparams.add(new BasicNameValuePair("btnG", "Google Search"));
    qparams.add(new BasicNameValuePair("aq", "f"));
    qparams.add(new BasicNameValuePair("oq", null));
    URI uri = URIUtils.createURI("http", "www.google.com", -1, "/search",
                                 URLEncodedUtils.format(qparams, "UTF-8"), null);
    HttpGet httpget = new HttpGet(uri);
    System.out.println(httpget.getURI());
    //http://www.google.com/search?q=httpclient&btnG=Google+Search&aq=f&oq=
}
}

编辑:从v4.2 URIUtils.createURI()开始不推荐使用以下内容URIBuilder:

URI uri = new URIBuilder()
        .setScheme("http")
        .setHost("www.google.com")
        .setPath("/search")
        .setParameter("q", "httpclient")
        .setParameter("btnG", "Google Search")
        .setParameter("aq", "f")
        .setParameter("oq", "")
        .build();
HttpGet httpget = new HttpGet(uri);
System.out.println(httpget.getURI());

Answer 2

作为作者,我可能不是判断我的URL/URI构建器是否良好的最佳人选,但它仍然是:https://github.com/mikaelhg/urlbuilder

我想要最简单的完整解决方案,在JDK之外没有依赖关系,所以我不得不自己动手.

Answer 3

Apache HTTPClient？

Answer 4

使用HTTPClient运行良好.

protected static String createUrl(List<NameValuePair> pairs) throws URIException{

  HttpMethod method = new GetMethod("http://example.org");
  method.setQueryString(pairs.toArray(new NameValuePair[]{}));

  return method.getURI().getEscapedURI();

}

Answer 5

有很多库可以帮助您构建URI(不要重新发明轮子).这里有三个让你入门:

Java EE 7

import javax.ws.rs.core.UriBuilder;
...
return UriBuilder.fromUri(url).queryParam(key, value).build();

org.apache.httpcomponents:HttpClient的:4.5.2

import org.apache.http.client.utils.URIBuilder;
...
return new URIBuilder(url).addParameter(key, value).build();

org.springframework:弹簧网:4.2.5.RELEASE

import org.springframework.web.util.UriComponentsBuilder;
...
return UriComponentsBuilder.fromUriString(url).queryParam(key, value).build().toUri();

另请参见: GIST> URI Builder测试

Answer 6

使用OkHttp

它是2018年,有一个非常受欢迎的名为OkHttp的图书馆,已经在GitHub上出演了27K次.使用此库,您可以构建如下所示的URL:

import okhttp3.HttpUrl;

URL url = new HttpUrl.Builder()
    .scheme("http")
    .host("example.com")
    .port(4567)
    .addPathSegment("foldername/1234")
    .addQueryParameter("abc", "xyz")
    .build().url();