HTTPClient 示例 - 线程“main"中的异常java.lang.NoSuchFieldError: INSTANCE [英] HTTPClient Example - Exception in thread "main" java.lang.NoSuchFieldError: INSTANCE

问题描述

我正在将 Apache 的 HttpClient 组件用于以下简单程序，但我看到以下异常:

<前>线程main"中的异常 java.lang.NoSuchFieldError: INSTANCE在 org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:52)在 org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:56)在 org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:46)在 org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:72)在 org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:84)在 org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:59)在 org.apache.http.impl.conn.PoolingHttpClientConnectionManager$InternalConnectionFactory.(PoolingHttpClientConnectionManager.java:487)在 org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:147)在 org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:136)在 org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:112)在 org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:726)在 com.starwood.rms.controller.property.HttpExample.main(HttpExample.java:14)

<前>公共类 HttpExample {公共静态无效主(字符串 [] args){HttpClient 客户端 = HttpClientBuilder.create().build();HttpGet 请求 = new HttpGet("https://www.google.com/?q=java");尝试 {HttpResponse 响应 = client.execute(request);System.out.println(response.getStatusLine());} 捕获(异常 e){e.printStackTrace();}}}

我正在使用

• Httpclient-4.3.3.jar
• Httpcore-4.3.2.jar

有什么想法吗?

解决方案

此代码有效...没有任何错误...如果您使用类似的导入，请检查包.

package com.jai.http;导入 org.apache.http.HttpResponse;导入 org.apache.http.client.HttpClient;导入 org.apache.http.client.methods.HttpGet;导入 org.apache.http.impl.client.HttpClientBuilder;公共类 HttpExample {/*** @param 参数*/公共静态无效主(字符串 [] args){HttpClient 客户端 = HttpClientBuilder.create().build();HttpGet 请求 = new HttpGet("https://www.google.com/?q=java");尝试 {HttpResponse 响应 = client.execute(request);System.out.println(response.getStatusLine());} 捕获(异常 e){e.printStackTrace();}}}

I am using HttpClient components from Apache for the following simple program and I see the below exception:

Exception in thread "main" java.lang.NoSuchFieldError: INSTANCE
    at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:52)
    at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:56)
    at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.(DefaultHttpRequestWriterFactory.java:46)
    at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:72)
    at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:84)
    at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.(ManagedHttpClientConnectionFactory.java:59)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager$InternalConnectionFactory.(PoolingHttpClientConnectionManager.java:487)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:147)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:136)
    at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.(PoolingHttpClientConnectionManager.java:112)
    at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:726)
    at com.starwood.rms.controller.property.HttpExample.main(HttpExample.java:14)

public class HttpExample {

    public static void main(String[] args) {
        HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet("https://www.google.com/?q=java");

        try {
            HttpResponse response = client.execute(request);
            System.out.println(response.getStatusLine());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

I am using

• Httpclient-4.3.3.jar
• Httpcore-4.3.2.jar

Any ideas?

解决方案

This code works...without any error.. check the packages if you are using similar import .

package com.jai.http;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;

public class HttpExample {

    /**
     * @param args
     */
    public static void main(String[] args) {
        HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet("https://www.google.com/?q=java");
        try {
            HttpResponse response = client.execute(request);
            System.out.println(response.getStatusLine());

        } catch (Exception e) {
            e.printStackTrace();

        }

    }
}

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