java中使用httpclient post请求时报空指针异常

Question

 maven ：
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>

相关代码：

         HttpPost httppost = new HttpPost("http://localadmin/xxxxx");
        List<NameValuePair> list = new ArrayList<NameValuePair>();
        list.add(new BasicNameValuePair("identityNum","xxxxx"));
        list.add(new BasicNameValuePair("channel","YT"));
        list.add(new BasicNameValuePair("userId","78652109462"));
        list.add(new BasicNameValuePair("userName","xxxxx"));
        list.add(new BasicNameValuePair("realName","xxxxx"));
        UrlEncodedFormEntity entity ;
        try {
            entity = new UrlEncodedFormEntity(list, "utf-8");

            httppost.setEntity(entity);
            ......

                    调试发现：

    在        super(URLEncodedUtils.format(parameters, charset != null?charset:HTTP.DEF_CONTENT_CHARSET.name()), ContentType.create("application/x-www-form-urlencoded", charset));处报
                        Method threw 'java.lang.NullPointerException' exception. Cannot evaluate org.apache.http.client.entity.UrlEncodedFormEntity.toString()

有同学遇到过吗？

Answer 1

调试看看这个类 UrlEncodedFormEntity 在这里引用的时候是不是null