java - 带有 maven 的 Jersey 2 客户端

Question

我想使用 Maven 创建简单的 Jersey 2 客户端应用程序(服务器应用程序也已实现并运行)。

我的 pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.client</groupId>
    <artifactId>RestClient</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>RestClient</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-client</artifactId>
            <version>2.13</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

java代码

package com.client;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Entity;
import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.Response;
import javax.ws.rs.client.Invocation.Builder;        

public class App 
{
    public static void main( String[] args )
    {

        Client client = ClientBuilder.newClient();
        WebTarget target = client.target("http://localhost:8080").path("simple-service-webapp/rest/myresource");

        Builder builder =   target.request();
        //Response response  = builder.get();
        String result  = builder.get(String.class);
        System.out.println(target.getUri().toString());
        System.out.println("Result=" + result);

    }
}

我通过命令 mvn package 构建应用程序，一切都通过了。然后，我通过 java -cp target/RestClient-1.0-SNAPSHOT.jar com.client.App 运行应用程序，然后发生错误:

Exception in thread "main" java.lang.NoClassDefFoundError: javax/ws/rs/client/ClientBuilder
        at com.client.App.main(App.java:20)
Caused by: java.lang.ClassNotFoundException: javax.ws.rs.client.ClientBuilder
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        ... 1 more

似乎没有包含库，因为 projeckt 的文件树看起来:

.
├── pom.xml
├── src
│   ├── main
│   │   └── java
│   │       └── com
│   │           └── client
│   │               └── App.java
│   └── test
│       └── java
│           └── com
│               └── client
│                   └── AppTest.java
└── target
    ├── classes
    │   └── com
    │       └── client
    │           └── App.class
    ├── generated-sources
    │   ├── annotations
    │   └── test-annotations
    ├── maven-archiver
    │   └── pom.properties
    ├── RestClient-1.0-SNAPSHOT.jar
    ├── surefire
    ├── surefire-reports
    │   ├── com.client.AppTest.txt
    │   └── TEST-com.client.AppTest.xml
    └── test-classes
        └── com
            └── client
                └── AppTest.class

我错在哪里了？谢谢。

Answer 1

您需要将依赖项从您的本地存储库复制到您的项目中(或者任何地方，任何您想要 -cp 的地方)。为此，您可以使用 maven-dependency-plugin .只需将其添加到 <plugins>

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <version>2.9</version>
    <executions>
        <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>copy-dependencies</goal>
            </goals>
            <configuration>
                <outputDirectory>${project.build.directory}/lib</outputDirectory>
                <overWriteReleases>false</overWriteReleases>
                <overWriteSnapshots>false</overWriteSnapshots>
                <overWriteIfNewer>true</overWriteIfNewer>
            </configuration>
        </execution>
    </executions>
</plugin>

上面的插件配置所做的是将所有依赖项复制到target/lib。 .

将 jar 作为可执行文件运行的最简单方法是同时设置 Class-Path在MANIFEST.MF ，通过 Maven。为此，我们可以使用 maven-jar-plugin .所以将其添加到 <plugins>

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <version>2.5</version>
    <configuration>
        <archive>
            <index>true</index>
            <manifest>
                <addClasspath>true</addClasspath>
                <classpathPrefix>lib/</classpathPrefix>
                <mainClass>com.client.App</mainClass>
            </manifest>
        </archive>
    </configuration>
</plugin>

您还需要摆脱 <scope>provided</scope>对于 Jersey 客户端依赖项。使用此范围，Maven 不会将 jars 添加到类路径。

完成此操作后，您可以简单地运行 java -jar your-jar.jar ，不需要 -cp 任何东西，因为所有的 jar 都在 list 中指定。它应该看起来像

Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Built-By: XxxxXxxxx
Class-Path: lib/jersey-client-2.13.jar lib/jersey-common-2.13.jar lib/
 javax.annotation-api-1.2.jar lib/jersey-guava-2.13.jar lib/osgi-resou
 rce-locator-1.0.1.jar lib/javax.ws.rs-api-2.0.1.jar lib/hk2-api-2.3.0
 -b10.jar lib/hk2-utils-2.3.0-b10.jar lib/aopalliance-repackaged-2.3.0
 -b10.jar lib/javax.inject-2.3.0-b10.jar lib/hk2-locator-2.3.0-b10.jar
  lib/javassist-3.18.1-GA.jar
Created-By: Apache Maven 3.0.5
Build-Jdk: 1.8.0_20
Main-Class: com.client.App