commons httpclient - 将查询字符串参数添加到 GET/POST 请求

Question

我正在使用 commons HttpClient 对 Spring servlet 进行 http 调用。我需要在查询字符串中添加一些参数。所以我做了以下事情：

HttpRequestBase request = new HttpGet(url);
HttpParams params = new BasicHttpParams();
params.setParameter("key1", "value1");
params.setParameter("key2", "value2");
params.setParameter("key3", "value3");
request.setParams(params);
HttpClient httpClient = new DefaultHttpClient();
httpClient.execute(request);

但是，当我尝试使用 servlet 读取参数时

((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest().getParameter("key");

它返回空值。实际上 parameterMap 是完全空的。当我在创建 HttpGet 请求之前手动将参数附加到 url 时，参数在 servlet 中可用。当我使用附加了 queryString 的 URL 从浏览器中点击 servlet 时也是如此。

这里有什么错误？在 httpclient 3.x 中，GetMethod 有一个 setQueryString() 方法来附加查询字符串。 4.x 中的等价物是什么？

Answer 1

我正在使用 Java 8 和 apache httpclient 4.5.13

HashMap<String, String> customParams = new HashMap<>();
customParams.put("param1", "ABC");
customParams.put("param2", "123");

URIBuilder uriBuilder = new URIBuilder(baseURL);

for (String paramKey : customParams.keySet()) {
    uriBuilder.addParameter(paramKey, customParams.get(paramKey));
}

System.out.println(uriBuilder.build().toASCIIString()); // ENCODED URL
System.out.println(uriBuilder.build().toString); // NORMAL URL

DTO 的完整示例

public class HttpResponseDTO {
    private Integer statusCode;
    private String body;
    private String errorMessage;
    
    public Integer getStatusCode() {
        return statusCode;
    }
    public void setStatusCode(Integer statusCode) {
        this.statusCode = statusCode;
    }
    public String getBody() {
        return body;
    }
    public void setBody(String body) {
        this.body = body;
    }
    public String getErrorMessage() {
        return errorMessage;
    }
    public void setErrorMessage(String errorMessage) {
        this.errorMessage = errorMessage;
    }
}

    /**
     * 
     * @param destinationURL
     * @param params
     * @param headers
     * @return HttpResponseDTO
     */
    public static HttpResponseDTO get(String baseURL, Boolean encodeURL, HashMap<String, String> params, HashMap<String, String> headers) {

        final HttpResponseDTO httpResponseDTO = new HttpResponseDTO();      

        // ADD PARAMS IF
        if (params != null && Boolean.FALSE.equals(params.isEmpty())) {
            URIBuilder uriBuilder;
            try {
                uriBuilder = new URIBuilder(baseURL);

                for (String paramKey : params.keySet()) {
                    uriBuilder.addParameter(paramKey, params.get(paramKey));
                }

                // CODIFICAR URL ?
                if (Boolean.TRUE.equals(encodeURL)) {
                    baseURL = uriBuilder.build().toASCIIString();
                } else {
                    baseURL = uriBuilder.build().toString();
                }
            } catch (URISyntaxException e) {
                httpResponseDTO.setStatusCode(500);
                httpResponseDTO.setErrorMessage("ERROR AL CODIFICAR URL: " + e.getMessage());
                return httpResponseDTO;
            }
        }


        // HACER PETICION HTTP
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {            
            final HttpGet get = new HttpGet(baseURL);   

            // ADD HEADERS
            if (headers != null && Boolean.FALSE.equals(headers.isEmpty())) {           
                for (String headerKey : headers.keySet()) {
                    get.setHeader(headerKey, headers.get(headerKey));
                }           
            }

            try (CloseableHttpResponse response = httpClient.execute(get);) {
                HttpEntity httpEntity = response.getEntity();
                if (httpEntity != null) {
                    httpResponseDTO.setBody(EntityUtils.toString(httpEntity));
                    httpResponseDTO.setStatusCode(response.getStatusLine().getStatusCode());
                }
            } catch(Exception e) {
                httpResponseDTO.setStatusCode(500);
                httpResponseDTO.setErrorMessage(e.getMessage());
                return httpResponseDTO;
            }
        } catch(Exception e) {
            httpResponseDTO.setStatusCode(500);
            httpResponseDTO.setErrorMessage(e.getMessage());
            return httpResponseDTO;
        }

        return httpResponseDTO;
    }

Answer 2

这就是我实现 URL 构建器的方式。 我创建了一个服务类来提供 URL 的参数

public interface ParamsProvider {

    String queryProvider(List<BasicNameValuePair> params);

    String bodyProvider(List<BasicNameValuePair> params);
}

方法的实现如下

@Component
public class ParamsProviderImp implements ParamsProvider {
    @Override
    public String queryProvider(List<BasicNameValuePair> params) {
        StringBuilder query = new StringBuilder();
        AtomicBoolean first = new AtomicBoolean(true);
        params.forEach(basicNameValuePair -> {
            if (first.get()) {
                query.append("?");
                query.append(basicNameValuePair.toString());
                first.set(false);
            } else {
                query.append("&");
                query.append(basicNameValuePair.toString());
            }
        });
        return query.toString();
    }

    @Override
    public String bodyProvider(List<BasicNameValuePair> params) {
        StringBuilder body = new StringBuilder();
        AtomicBoolean first = new AtomicBoolean(true);
        params.forEach(basicNameValuePair -> {
            if (first.get()) {
                body.append(basicNameValuePair.toString());
                first.set(false);
            } else {
                body.append("&");
                body.append(basicNameValuePair.toString());
            }
        });
        return body.toString();
    }
}

当我们需要 URL 的查询参数时，我只需调用服务并构建它。 示例如下。

Class Mock{
@Autowired
ParamsProvider paramsProvider;
 String url ="http://www.google.lk";
// For the query params price,type
 List<BasicNameValuePair> queryParameters = new ArrayList<>();
 queryParameters.add(new BasicNameValuePair("price", 100));
 queryParameters.add(new BasicNameValuePair("type", "L"));
url = url+paramsProvider.queryProvider(queryParameters);
// You can use it in similar way to send the body params using the bodyProvider

}

Answer 3

我正在使用 httpclient 4.4。

对于 solr 查询，我使用了以下方式，并且成功了。

NameValuePair nv2 = new BasicNameValuePair("fq","(active:true) AND (category:Fruit OR category1:Vegetable)");
nvPairList.add(nv2);
NameValuePair nv3 = new BasicNameValuePair("wt","json");
nvPairList.add(nv3);
NameValuePair nv4 = new BasicNameValuePair("start","0");
nvPairList.add(nv4);
NameValuePair nv5 = new BasicNameValuePair("rows","10");
nvPairList.add(nv5);

HttpClient client = HttpClientBuilder.create().build();
HttpGet request = new HttpGet(url);
URI uri = new URIBuilder(request.getURI()).addParameters(nvPairList).build();
            request.setURI(uri);

HttpResponse response = client.execute(request);    
if (response.getStatusLine().getStatusCode() != 200) {

}

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

String output;
System.out.println("Output  .... ");
String respStr = "";
while ((output = br.readLine()) != null) {
    respStr = respStr + output;
    System.out.println(output);
}

Answer 4

以下是使用 HttpClient 4.2 及更高版本添加查询字符串参数的方法：

URIBuilder builder = new URIBuilder("http://example.com/");
builder.setParameter("parts", "all").setParameter("action", "finish");

HttpPost post = new HttpPost(builder.build());

生成的 URI 如下所示：

http://example.com/?parts=all&action=finish

Answer 5

这种方法可以，但不适用于动态获取参数时，有时是 1、2、3 或更多，就像 SOLR 搜索查询（例如）

这是一个更灵活的解决方案。粗制滥造，但可以精炼。

public static void main(String[] args) {

    String host = "localhost";
    String port = "9093";

    String param = "/10-2014.01?description=cars&verbose=true&hl=true&hl.simple.pre=<b>&hl.simple.post=</b>";
    String[] wholeString = param.split("\\?");
    String theQueryString = wholeString.length > 1 ? wholeString[1] : "";

    String SolrUrl = "http://" + host + ":" + port + "/mypublish-services/carclassifications/" + "loc";

    GetMethod method = new GetMethod(SolrUrl );

    if (theQueryString.equalsIgnoreCase("")) {
        method.setQueryString(new NameValuePair[]{
        });
    } else {
        String[] paramKeyValuesArray = theQueryString.split("&");
        List<String> list = Arrays.asList(paramKeyValuesArray);
        List<NameValuePair> nvPairList = new ArrayList<NameValuePair>();
        for (String s : list) {
            String[] nvPair = s.split("=");
            String theKey = nvPair[0];
            String theValue = nvPair[1];
            NameValuePair nameValuePair = new NameValuePair(theKey, theValue);
            nvPairList.add(nameValuePair);
        }
        NameValuePair[] nvPairArray = new NameValuePair[nvPairList.size()];
        nvPairList.toArray(nvPairArray);
        method.setQueryString(nvPairArray);       // Encoding is taken care of here by setQueryString

    }
}

Answer 6

如果您想在创建请求后添加查询参数，请尝试将 HttpRequest 强制转换为 HttpBaseRequest。然后你可以改变被转换的请求的 URI：

HttpGet someHttpGet = new HttpGet("http://google.de");

URI uri = new URIBuilder(someHttpGet.getURI()).addParameter("q",
        "That was easy!").build();

((HttpRequestBase) someHttpGet).setURI(uri);

Answer 7

HttpParams 接口不是用于指定查询字符串参数，而是用于指定HttpClient 对象的运行时行为。

如果要传递查询字符串参数，需要自己在URL上组装，例如

new HttpGet(url + "key1=" + value1 + ...);

记得先对值进行编码（使用URLEncoder）。