Jersey + Spark javax.ws.rs.core.UriBuilder.uri

Question

我正在使用 Jersey 2 + spring 开发一个 Restful 服务。在同一个项目中，我依赖 Spark 2.0.11。但是一旦将 spark 依赖项添加到项目中，调用 Restful 服务就会引发以下异常。例外：

SEVERE: Servlet.service() for servlet [jersey-serlvet] in context with path [/recommender] threw exception [Servlet execution threw an exception] with root cause
java.lang.AbstractMethodError: javax.ws.rs.core.UriBuilder.uri(Ljava/lang/String;)Ljavax/ws/rs/core/UriBuilder;
    at javax.ws.rs.core.UriBuilder.fromUri(UriBuilder.java:119)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:298)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:228)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:958)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:452)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1087)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

pom.xml：

<properties>
    <org.springframework-version>4.0.0.RELEASE</org.springframework-version>
    <jersey2.version>2.19</jersey2.version>
    <jaxrs.version>2.0.1</jaxrs.version>
  </properties>
<dependency>
        <groupId>org.apache.spark</groupId>
        <artifactId>spark-core_2.11</artifactId>
        <version>2.0.0</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-mllib_2.10 -->
    <dependency>
        <groupId>org.apache.spark</groupId>
        <artifactId>spark-mllib_2.11</artifactId>
        <version>2.0.0</version>
    </dependency>

  <!-- JAX-RS -->
        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>javax.ws.rs-api</artifactId>
            <version>${jaxrs.version}</version>
        </dependency>
        <!-- Jersey 2.19 -->
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-server</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-client</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
    <dependency>
      <groupId>io.swagger</groupId>
      <artifactId>swagger-jersey-jaxrs</artifactId>
      <version>1.5.0</version>
      <!-- <exclusions>
        <exclusion>
            <artifactId>jersey-multipart</artifactId>
            <groupId>com.sun.jersey.contribs</groupId>
        </exclusion>
      </exclusions> -->
    </dependency>

    <!-- spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>



    <!-- jersey + spring -->
    <dependency>
        <groupId>com.sun.jersey.contribs</groupId>
        <artifactId>jersey-spring</artifactId>
        <version>1.9</version>
        <exclusions>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring-core</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.springframework</groupId>
                <artifactId>spring-asm</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

web.xml

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
    id="WebApp_ID" version="2.5">
    <display-name>WebApp</display-name>

    <!-- <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param> -->

    <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>

    <servlet>
        <servlet-name>jersey-serlvet</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
             <param-name>jersey.config.server.provider.packages</param-name>
             <param-value>com.company.recommender.rest.v1</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet>
        <servlet-name>Jersey2Config</servlet-name>
        <servlet-class>io.swagger.jaxrs.config.DefaultJaxrsConfig</servlet-class>
        <init-param>
            <param-name>api.version</param-name>
            <param-value>1.0.0</param-value>
        </init-param>
        <init-param>
            <param-name>swagger.api.basepath</param-name>
            <param-value>http://localhost:8085/recommender/rest/v1</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>jersey-serlvet</servlet-name>
        <url-pattern>/rest/v1/*</url-pattern>
    </servlet-mapping> 

</web-app>

我知道问题是 UriBuilder 类的冲突定义（在许多包含的库中都可以找到）。所以有什么建议。

Answer 1

实际上 Spark 2.0 引入了 jersey 2.x 与

[INFO] |  +- org.glassfish.jersey.core:jersey-client:jar:2.22.2:compile
[INFO] |  |  +- javax.ws.rs:javax.ws.rs-api:jar:2.0.1:compile

当 jersey-spring 引入 jersey 1.x 时， 两者都有一些共同的类，但实现方式不同。

现在，让我们看看错误

java.lang.AbstractMethodError: javax.ws.rs.core.UriBuilder.uri(Ljava/lang/String;)Ljavax/ws/rs/core/UriBuilder;

所以它说它遇到了UriBuilder 实例的抽象方法。一般来说，Java 编译器不允许使用抽象类（具有抽象方法）创建实例。所以你可以清楚地得出结论，编译时和运行时使用的类是不同的。让我们看看类在运行时是如何变化的，看看javax.ws.rs.core.UriBuilder.fromUri方法跟踪的源代码：

public static UriBuilder fromUri(URI uri) {
    return newInstance().uri(uri);
}

需要

protected static UriBuilder newInstance() {
        return RuntimeDelegate.getInstance().createUriBuilder();
}

解决方法：

public static RuntimeDelegate getInstance() {

        RuntimeDelegate result = cachedDelegate;
        if (result == null) { // First check (no locking)
            synchronized (RD_LOCK) {
                result = cachedDelegate;
                if (result == null) { // Second check (with locking)
                    cachedDelegate = result = findDelegate();
                }
            }
        }
        return result;
    }

它正在调用RuntimeDelegate.findDelegate()，它将创建RuntimeDelegate 的实现，而RuntimeDelegate 又将用于创建UriBuilder。由于运行时类路径不匹配，它解析为com.sun.jersey.api.uri.UriBuilderImpl（来自球衣1），它没有实现抽象方法public abstract UriBuilder uri(String uriTemplate);（因为它是从2.0引入的）。为了避免这种情况，我刚刚做了

    RuntimeDelegate.setInstance(new org.glassfish.jersey.internal.RuntimeDelegateImpl());

在应用程序的开头。这反过来为org.glassfish.jersey.uri.internal.JerseyUriBuilder（非抽象类）创建了正确的实现。它实际上在RuntimeDelegate 中设置了名为cachedDelegate 的静态成员。

由于它只是 URI 解析，因此不同的库可能会起作用。给定的类与球衣 1 和球衣 2 完全兼容。如果有人为此找到任何其他库，请告诉我。