上下文初始化时的 Jersey ClassNotFoundException

Question

当我连接到选定的 servlet 时，它会抛出 ClassNotFoundException。我正在使用带有 Tomcat8 和 jersey RESTful 框架的 eclipse neon。有可能我在 web.xml 中有错误的 servlet conf 吗？

错误显示：

SEVERE: Allocate exception for servlet jersey
java.lang.ClassNotFoundException: org.glassfish.jersey.servlet.ServletContainer
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1332)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1166)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:518)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:499)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1102)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:828)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

我的 web.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
  <display-name>org.CTAG.DATEX2REST</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <display-name>CTAG DATEX2</display-name>

    <servlet>
        <servlet-name>jersey</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>org.CTAG.DATEX2REST</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>jersey</servlet-name>
        <url-pattern>/rest</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>
            com.CTAG.application.Init
        </listener-class>
    </listener>
</web-app>

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>org.CTAG.DATEX2REST</groupId>
    <artifactId>org.CTAG.DATEX2REST</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>org.CTAG.DATEX2REST Maven Webapp</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>com.sun.jersey</groupId>
            <artifactId>jersey-server</artifactId>
            <version>1.9</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
    <build>
        <finalName>org.CTAG.DATEX2REST</finalName>
        <sourceDirectory>src/main/java</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <warSourceDirectory>WebContent</warSourceDirectory>
                    <failOnMissingWebXml>true</failOnMissingWebXml>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

您的web.xml 内容不正确，它与Jersey 2.x 匹配，而您显然使用Jersey 1.x，确实包名称在Jersey 1.x 中以com.sun.jersey 开头，而在Jersey 2.x 中它们以org.glassfish.jersey 开头。

如果是Jersey 1.x.，请检查here web.xml 的内容。

<servlet>
    <servlet-name>jersey</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>com.sun.jersey.config.property.packages</param-name>
        <param-value>org.CTAG.DATEX2REST</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <servlet-name>jersey</servlet-name>
    <url-pattern>/rest</url-pattern>
</servlet-mapping>

或切换到Jersey 2.x。

Answer 2

修复依赖关系

您正在混合 Jersey 1.x (com.sun.jersey) 和 Jersey 2.x (org.glassfish.jersey)。

我知道你不想使用 Jersey 2.x，所以删除：

<dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-server</artifactId>
    <version>1.9</version>
</dependency>

然后添加到您的pom.xml

<dependency>
    <groupId>org.glassfish.jersey.containers</groupId>
    <!-- if your container implements Servlet API older 
         than 3.0, use "jersey-container-servlet-core"  -->
    <artifactId>jersey-container-servlet</artifactId>
    <version>2.23.2</version>
</dependency>

在 Servlet 2.x 容器（如 Tomcat 6）中部署

Jersey 与任何至少支持 Servlet 2.5 规范的 Servlet 容器集成。对于这些环境，您必须在 Web 应用程序的 web.xml 部署描述符文件中显式声明 Jersey 容器 servlet：

<web-app>

    <servlet>
        <servlet-name>MyApplication</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            ...
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>MyApplication</servlet-name>
        <url-pattern>/api/*</url-pattern>
    </servlet-mapping>

</web-app>

<init-param> 元素的内容将根据您决定配置 Jersey 资源的方式而有所不同。

在 Servlet 3.x 容器中部署（如 Tomcat 7 及更高版本）

在 Servlet 3.0 容器中，您只需要实现一个自定义的 Application / ResourceConfig 子类。对于简单的部署，根本不需要web.xml。相反，@ApplicationPath 注释可用于注释自定义 Application / ResourceConfig 子类，并为应用程序中配置的所有 JAX-RS 资源定义基本应用程序 URI：

@ApplicationPath("api")
public class MyApplication extends ResourceConfig {

    public MyApplication() {
        packages("org.foo.rest;org.bar.rest");
    }
}

---

有关其他部署选项，请查看documentation。