无法与Gradle HttpClient依赖运行Jar

Question

在IntelliJ中使用gradle构建后，我尝试运行jar文件，但出现以下错误：

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/client/methods/HttpUriRequest
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
    at java.lang.Class.getMethod0(Class.java:3018)
    at java.lang.Class.getMethod(Class.java:1784)
    at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.apache.http.client.methods.HttpUriRequest
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

我的build.gradle看起来像这样：

dependencies {
    compile 'org.apache.httpcomponents:httpclient:4.5.3'

    testCompile group: 'junit', name: 'junit', version: '4.11'
}

我已经在IntelliJ的模块settigns中检查了httpcomponents和commons-codec的依赖性。

源代码：

package com.jshah;

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;

import java.io.BufferedReader;
import java.io.InputStreamReader;

import static org.apache.http.HttpHeaders.USER_AGENT;


public class Runner {
    public static void main(String[] args) {
        final String url = "http://reddit.com/api/trending_subreddits";

        try {
            HttpClient client = HttpClientBuilder.create().build();
            HttpGet request = new HttpGet(url);

            request.addHeader("User-Agent", USER_AGENT);
            HttpResponse response = client.execute(request);

            System.out.println(response.getStatusLine());

            // Get the response
            BufferedReader rd = new BufferedReader
                    (new InputStreamReader(
                            response.getEntity().getContent()));

            String line;
            while ((line = rd.readLine()) != null) {
                System.out.println(line);
            }
        }
        catch (Exception e) {

        }
    }
}

Answer 1

您是否只是通过调用以下命令来构建项目：gradle build（不添加任何其他插件，除了Java）？ 如果是这样，则jar中没有httpclient类。 您需要使用FatJar或Copy依赖项来构建项目。

Answer 2

您还可以扩展jar任务以收集依赖关系并将其打包，但是请注意，这不是首选解决方案。 我仅将其用于某些小型应用程序或测试。 强烈建议使用插件。

jar {
archiveName = 'Name.jar'

manifest {
    attributes 'Main-Class': 'your main',
            'Class-Path': configurations.runtime.files.collect { "lib/$it.name" }.join(' '),
            'Implementation-Version': project.version
}

from(configurations.compile.collect { it.isDirectory() ? it : zipTree(it) })
}