• JavaWeb 发送post请求的2种方式(form、json)


    前提:通过HttpClient来实现

    方式一:以form表单形式提交数据

    1.所需jar包

      commons-logging-1.1.1.jar

      httpclient-4.5.jar

      httpcore-4.4.1.jar

    2.代码实现

      客户端如何发送请求?

      导入

    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    import org.apache.http.HttpResponse;
    import org.apache.http.HttpStatus;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    /**
     * 以form表单形式提交数据,发送post请求
     * @explain 
     *   1.请求头:httppost.setHeader("Content-Type","application/x-www-form-urlencoded")
     *   2.提交的数据格式:key1=value1&key2=value2...
     * @param url 请求地址
     * @param paramsMap 具体数据
     * @return 服务器返回数据
     */
    public static String httpPostWithForm(String url,Map<String, String> paramsMap){
        // 用于接收返回的结果
        String resultData ="";
         try {
                HttpPost post = new HttpPost(url);
                List<BasicNameValuePair> pairList = new ArrayList<BasicNameValuePair>();
                // 迭代Map-->取出key,value放到BasicNameValuePair对象中-->添加到list中
                for (String key : paramsMap.keySet()) {
                    pairList.add(new BasicNameValuePair(key, paramsMap.get(key)));
                }
                UrlEncodedFormEntity uefe = new UrlEncodedFormEntity(pairList, "utf-8");
                post.setEntity(uefe); 
                // 创建一个http客户端
                CloseableHttpClient httpClient = HttpClientBuilder.create().build();
                // 发送post请求
                HttpResponse response = httpClient.execute(post);
                
                // 状态码为:200
                if(response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                    // 返回数据:
                    resultData = EntityUtils.toString(response.getEntity(),"UTF-8");
                }else{
                    throw new RuntimeException("接口连接失败!");
                }
            } catch (Exception e) {
                throw new RuntimeException("接口连接失败!");
            }
         return resultData;
    }  

      服务器端如何接收客户端传递的数据?

      request.getParameter("key")

    3.客户端调用测试

    public static void main(String[] args) {
        String requestUrl = "http://localhost:8070/test/rz/server/rzxx/at_VaildToken.do";
        Map<String, String> paramsMap = new HashMap<String, String>(1);
        paramsMap.put("un_value", "B022420184794C7C9D5096CC5F3AE7D2");
        // 发送post请求并接收返回结果
        String resultData = httpPostWithForm(requestUrl, paramsMap);
        System.out.println(resultData);
    }

    方式二:以JSONObject形式提交数据

    1.所需jar包

    2.代码实现

      客户端如何发送请求?

      所需jar包:

      commons-httpclient-3.0.jar

      commons-codec-1.9.jar

      commons-logging-1.1.1.jar 

      导入

    import org.apache.commons.httpclient.HttpClient;
    import org.apache.commons.httpclient.HttpStatus;
    import org.apache.commons.httpclient.methods.PostMethod;
    import org.apache.commons.httpclient.methods.StringRequestEntity;
    /**
     * 以json格式字符串形式提交数据,发送post请求
     * @explain 
     *     1.请求头:httppost.setHeader("Content-Type","application/json")
     *  2.提交的数据格式:"{"key1":"value1","key2":"value2",...}"
     * @param jsonStr
     *            json字符串
     * @return 服务器返回数据
     */
    public static String sendPostWithJson(String url, String jsonStr) {
        // 用于接收返回的结果
        String jsonResult = "";
        try {
            HttpClient client = new HttpClient();
            client.getHttpConnectionManager().getParams().setConnectionTimeout(3000); // //设置连接超时
            client.getHttpConnectionManager().getParams().setSoTimeout(180000); // //设置读取数据超时
            client.getParams().setContentCharset("UTF-8");
            PostMethod postMethod = new PostMethod(url);
            postMethod.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
            // 非空
            if (null != jsonStr && !"".equals(jsonStr)) {
                StringRequestEntity requestEntity = new StringRequestEntity(jsonStr, "application/json", "UTF-8");
                postMethod.setRequestEntity(requestEntity);
            }
            int status = client.executeMethod(postMethod);
            if (status == HttpStatus.SC_OK) {
                jsonResult = postMethod.getResponseBodyAsString();
            } else {
                throw new RuntimeException("接口连接失败!");
            }
        } catch (Exception e) {
            throw new RuntimeException("接口连接失败!");
        }
        return jsonResult;
    }

      服务器端如何接收客户端传递的数据?

       所需jar包:

      commons-beanutils-1.8.0.jar

      commons-collections-3.2.1.jar

      commons-lang-2.5.jar

      commons-logging-1.1.1.jar

      ezmorph-1.0.6.jar

      json-lib-2.4-jdk15.jar

      导入

    import java.io.BufferedReader;
    import java.io.IOException;
    import javax.servlet.http.HttpServletRequest;
    import net.sf.json.JSONObject;
    /**
     * 获取接口传递的JSON数据
     * @explain
     * @param request
     *            HttpServletRequest对象
     * @return JSON格式数据
     */
    public static JSONObject getJsonReqData(HttpServletRequest request) {
        StringBuffer sb = new StringBuffer();
        JSONObject jo = null;
        BufferedReader reader = null;
        try {
            // json格式字符串
            String jsonStr = "";
            // 获取application/json格式数据,返回字符流
            reader = request.getReader();
            // 对字符流进行解析
            while ((jsonStr = reader.readLine()) != null) {
                sb.append(jsonStr);
            }
            
        } catch (IOException e) {
            log.error("request请求解析失败:" + e.getMessage());
            throw new RuntimeException("request请求解析失败:" + e.getMessage());
        } finally {// 关闭流,避免一直占用该流资源,导致浪费
            try {
                if (null != reader) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        log.info("接收的参数信息为:{}" + sb.toString());
        // 将json字符串(jsonStr)-->json对象(JSONObject)
        try {
            jo = JSONObject.fromObject(sb.toString());
        } catch (Exception e) {
            throw new RuntimeException("请求参数不是json格式数据!");
        }
        return jo;
    }

    3.客户端调用测试

    public static void main(String[] args) {
        String requestUrl = "http://localhost:8070/test/rz/server/rzxx/at_VaildToken.do";
        String jsonStr = "{"un_value":"B022420184794C7C9D5096CC5F3AE7D2"}";
        // 发送post请求并接收返回结果
        String resultData = sendPostWithJson(requestUrl, jsonStr);
        System.out.println(resultData);
    }

    4.服务端接收测试

    public static void main(String[] args) {
        //获取接口json数据  
        JSONObject jsonRequest = getJsonReqData(WebUtils.getRequest());
        String s = jsonRequest.get("un_value").toString();// B022420184794C7C9D5096CC5F3AE7D2
        //
        s = jsonRequest.getString("un_value");// B022420184794C7C9D5096CC5F3AE7D2
    }

    PS:20191211(合并版)

    java作为客户端,去请求另一台服务器,数据格式完全可以以流的形式进行传送和接收,这样不管是form表单还是json都可以采用一种方式搞定。

    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import org.apache.commons.lang3.StringUtils;
    
    /**
     * java发送post请求(暂时只支持form表单提交和json数据提交两种方式,还可以根据需要自行扩展)
     * @expalin 说明:
     *          form表单提交,要求参数格式必须是遵循form参数规范;
     *          json数据提交,要求参数格式必须是遵循json标准规范。
     * @param url
     *            服务器地址
     * @param param
     *            请求参数
     *            格式一:form表单形式,param1=value1&param2=value2&...
     *            格式二:json数据形式,{"param1":"value1","param2":"value2",...}
     * @param contentType
     *            数据类型(暂时提供两种)
     *            格式一:form表单,application/x-www-form-urlencoded
     *            格式二:json数据,application/json
     * @param charset
     *            字符集
     *            如果不传,默认值为:utf-8
     */
    public static String sendPostRequest(String url, String param, String contentType, String charset) {
        // 请求方法:post、get
        String requestMethod = "POST";
        // 数据类型
        if ("form".equals(contentType)) {
            contentType = "application/x-www-form-urlencoded";
        } else if ("json".equals(contentType)) {
            contentType = "application/json";
        }
        // 告诉请求数据的字符集
        charset = "".equals(charset) ? "utf-8" : charset;
    
        // 用于接收服务器返回结果
        StringBuffer responseResult = new StringBuffer();
        HttpURLConnection conn = null;
        OutputStream out = null;
        BufferedReader reader = null;
        try {
            // 打开网址
            URL requestUrl = new URL(url);
            conn = (HttpURLConnection) requestUrl.openConnection();
            // 连接设置
            conn.setRequestMethod(requestMethod);
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("Content-Type", contentType + ";" + charset);
            // 进行连接
            conn.connect();
            // 将数据以流的形式进行传输(二进制)
            out = conn.getOutputStream();
            out.write(param.getBytes());
            out.flush();
    
            // 响应状态码:200-代表正常
            int responseCode = conn.getResponseCode();
            if (responseCode != 200) {
                throw new RuntimeException("Error responseCode:" + responseCode);
            }
    
            // 获取服务器响应数据字符集
            String responseEncoding = conn.getContentEncoding();
            responseEncoding = StringUtils.isEmpty(responseEncoding) ? "utf-8" : responseEncoding;
            // 读取服务器响应数据
            String output = null;
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), responseEncoding));
            while ((output = reader.readLine()) != null) {
                responseResult.append(output);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("调用接口出错:param=" + param);
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
                if (out != null) {
                    out.close();
                }
                if (conn != null) {
                    conn.disconnect();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return responseResult.toString();
    }
    

    20200403

      这样的话,接收数据的服务器不用再区分传过来的是form表单还是json,统一按照接收json那样以字符流的形式进行读取即可。

      当然了,这还得和服务器协商好,不然你传过去的是二进制,它却还是按照request.getParameter(),服务器肯定接收不到。

      另外,如果是浏览器按照application/x-www-form-urlencoded的编码格式向后台传递数据的话,服务器只能用request.getParameter()来接收,这才是规范用法。

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  • 原文地址:https://www.cnblogs.com/Marydon20170307/p/9202987.html
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