tomcat与jetty接收请求参数的区别

【场景】
服务端点对点通知。
A服务发起请求B服务，B同步返回接收成功；然后B开始处理逻辑；B处理完成后异步通知给A；A接收请求并处理，同步回写响应给B；完成。

【先上代码】
服务端（接收端）代码：

客户端（请求端）HttpUtil工具类：

客户端测试方法：

【测试结论】
Tomcat和jetty对于HttpServletRequest.getParameterMap()的处理不同。jetty可以直接获取到请求参数；而Tomcat获取不到。下面是Tomcat的日志：

六月 11, 2019 10:11:53 上午 org.apache.tomcat.util.http.Parameters processParameters
信息: Character decoding failed. Parameter [{"interfaceName":"RegisterNotify","merSignMsg":"APrWHHydX41atXjfadKBfDPUhKBQbZ6fTKcnHGtVBhe9qpSfArVqRFrlf2wgw9gzmMnGo3x15XKXAZnC51WU60FXNVj2kaxpWYzpuh6rvUDrDVQV6Z7SHEI8GvrMLE8uOG2TPR0Xu6v71o8u8TJsWsiVOP/ncsAHSzSz%%2B2Ch7N3E5ePCQi84To7LvSO5HrtUUmTbc%2BrmG2frJfYJNfvsxuGvt9U2MqmFeWFE98fK5e5SFUSSZLtqj42N18ppSZWSxN3MleGDTsy75zR3JxO6ol99lCPea4zqLmnUoEFlnJ3J6vXXUVXnMuSX5Mw%3D%3D","merchantId":"M100002734","tranData":"PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iR0JLIiA%2FPjxCMkNSZXM%2BPHN0YXR1cz4wPC9zdGF0dXM%2BPGJpbmRTdHM%2BMTwvYmluZFN0cz48Y3VzdG9tZXJJZD5DMTAwMDE0Mjc1PC9jdXN0b21lcklkPjxjb21wYW55PtDs1t3TzrHpzOzPwsLD087Qxc%2Bi18nRr9PQz965q8u%2BPC9jb21wYW55PjxyZWZ1c2VSZWFzb24vPjwvQjJDUmVzPg%3D%3D","version":"B2C1.0"}] with value [] has been ignored. Note that the name and value quoted here may be corrupted due to the failed decoding. Use debug level logging to see the original, non-corrupted values.
Note: further occurrences of Parameter errors will be logged at DEBUG level.

map count:0

Character decoding failed.Parameter [dd] with value [] has been ignored. 百度翻译为：字符解码失败。已忽略值为[]的参数[dd]。

我的Tomcat版本是7.0.93;jetty版本是6.1.26。通过比较两者的servlet-api.jar，发现Tomcat7的servlet-api的版本是3.0，而jetty的servlet-api的版本是2.5。或许是这种版本的差异导致结果不同。试图跟踪源码来一识庐山真面目，jetty的进去了，但从RequestWapper类里也看不到什么；Tomcat的则进不去。

进一步通过Tomcat测试发现：请求参数里的merSignMsg，当我改变其值（去掉开头的一些字符）时，Tomcat就能获取到了。看来还是Tomcat处理字符编码的问题。

【话说回来】
话说回来，上面案例content-type用form实在不合适，因为想获取到请求数据，得取key的值而不是value，这不符合常用的套路啊，由此我的同事那天在接收数据时很费了一番折腾。像这种上送json字符串的，改用text/plain更合适。这样的话，接收端通过读取HttpServletRequest的输入流就可以获取到请求数据。

附上读取HttpServletRequest流的代码：

package com;

import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class ReadHttpRequest {

    /**
     * 从request.ParameterMap获取数据---适用于表单请求
     * @param request
     * @return
     * @throws UnsupportedEncodingException
     * @throws Exception
     */
    public static Map getRequestMap(HttpServletRequest request) throws UnsupportedEncodingException,Exception {
        Map result = new HashMap();
        Map<String, String[]> map = request.getParameterMap();
        if (0 == map.size()) {
            System.out.println("未获取到任何请求参数.");
//            throw new  Exception("未获取到任何请求参数.");
            return result;
        }

        for (Iterator iter = map.entrySet().iterator(); iter.hasNext(); ) {
            Map.Entry element = (Map.Entry) iter.next();
            Object strKey = element.getKey();  //key值
            String[] value = (String[]) element.getValue(); //value,数组形式
            String values = "";
            for (int i = 0; i < value.length; i++) {
                values += "," + value[i];
            }
            result.put(strKey.toString(), values.replaceFirst(",", ""));
        }
        return result;
    }


    /**
     * 从输入流获取数据---适用于流请求
     * @param request
     * @return
     */
    public static String getRequestInputStream(HttpServletRequest request) {
        InputStream in = null;
        ByteArrayOutputStream out = null;
        try {
            in = request.getInputStream();
            out = new ByteArrayOutputStream();
            in2OutStream(in, out, 1024 * 1024);
            return out.toString("UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if (in != null) in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }
    private static void in2OutStream(InputStream in, OutputStream out,
                                     int bufferSize) throws IOException {
        byte[] buffer = new byte[bufferSize];// 缓冲区
        for (int bytesRead = 0; (bytesRead = in.read(buffer)) != -1; ) {
            out.write(buffer, 0, bytesRead);
            Arrays.fill(buffer, (byte) 0);
        }
    }
}

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