Question

尝试使用Jersey创建一个简单的RESTful Web服务并将其部署在Tomcat 7上。由于我是Java新手，并渴望学习它，所以我跟随this tutorial

我在Eclipse中将此应用程序创建为Maven项目，并将jersey-quickstart-webapp工件版本2.22.2与org.glassfish.jersey.archetypes groupID一起使用。请注意，我必须稍后将Project Facet更改为Dynamic Web Module否则它不会给我一个将其部署到本地Tomcat服务器的选项。

我已将messenger应用添加为Tomcat服务器中的资源。在Eclipse中启动Tomcat服务器时，我没有看到任何错误。只有一个警告 WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:messenger' did not find a matching property.，根据很多SO帖子，可以安全地忽略。

右键点击该应用并点击Run As - ＆gt; Run on Server，我发现网址http://localhost:8080/messenger/以及http://localhost:8080/webapi/myresource找不到404页面。

检查过很多类似的SO帖子，例如this和this但是他们没有帮助。

我注意到的一件事是web.xml内的<peoject_root>/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/ROOT/WEB-INF与我的应用的web.xml不匹配（在部署应用后不确定它是否匹配）到Tomcat）。事实上，该目录下的内容复制如下：

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">

需要一些关于可能出错的指示。这可能是一件简单的事情，但是我花了很多时间在这个问题上挣扎并在第n次出现同样的404错误。在我有信心并继续观看培训视频之前，我希望能够让这个简单的应用程序工作。

通过屏幕截图和文件内容添加更多细节：

MyResource.java

package org.testapp.java.messenger;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

/**
 * Root resource (exposed at "myresource" path)
 */
@Path("myresource")
public class MyResource {

    /**
     * Method handling HTTP GET requests. The returned object will be sent
     * to the client as "text/plain" media type.
     *
     * @return String that will be returned as a text/plain response.
     */
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getIt() {
        return "Got it!";
    }
}

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- This web.xml file is not required when using Servlet 3.0 container,
     see implementation details http://jersey.java.net/nonav/documentation/latest/jax-rs.html -->
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>Jersey Web Application</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.testapp.java.messenger</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Jersey Web Application</servlet-name>
        <url-pattern>/webapi/*</url-pattern>
    </servlet-mapping>
</web-app>

项目结构

Tomcat错误

您在代码中看到的一个RED十字架是实际The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path，教程视频中的讲师要求忽略，因为Tomcat提供了HTTPServlet类。

控制台输出

May 01, 2016 10:09:20 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:messenger' did not find a matching property.
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version:        Apache Tomcat/7.0.69
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server built:          Apr 11 2016 07:57:09 UTC
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server number:         7.0.69.0
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Name:               Mac OS X
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Version:            10.10.2
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Architecture:          x86_64
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Java Home:             /Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/jre
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Version:           1.8.0_31-b13
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Vendor:            Oracle Corporation
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_BASE:         /Users/abc/Personal/Java/.metadata/.plugins/org.eclipse.wst.server.core/tmp0
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_HOME:         /Users/abc/Personal/Java/apache-tomcat-7.0.69
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.base=/Users/abc/Personal/Java/.metadata/.plugins/org.eclipse.wst.server.core/tmp0
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.home=/Users/abc/Personal/Java/apache-tomcat-7.0.69
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dwtp.deploy=/Users/abc/Personal/Java/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Djava.endorsed.dirs=/Users/abc/Personal/Java/apache-tomcat-7.0.69/endorsed
May 01, 2016 10:09:20 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dfile.encoding=UTF-8
May 01, 2016 10:09:20 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /Users/abc/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.
May 01, 2016 10:09:20 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
May 01, 2016 10:09:20 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
May 01, 2016 10:09:20 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 434 ms
May 01, 2016 10:09:20 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
May 01, 2016 10:09:20 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.69
May 01, 2016 10:09:20 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8080"]
May 01, 2016 10:09:20 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
May 01, 2016 10:09:20 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 269 ms

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>org.testapp.java</groupId>
    <artifactId>messenger</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>messenger</name>

    <build>
        <finalName>messenger</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <inherited>true</inherited>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.glassfish.jersey</groupId>
                <artifactId>jersey-bom</artifactId>
                <version>${jersey.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet-core</artifactId>
            <!-- use the following artifactId if you don't need servlet 2.x compatibility -->
            <!-- artifactId>jersey-container-servlet</artifactId -->
        </dependency>
        <!-- uncomment this to get JSON support
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-moxy</artifactId>
        </dependency>
        -->
    </dependencies>
    <properties>
        <jersey.version>2.22.2</jersey.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
</project>

Answer 1

在servlet条目之前，在web.xml中添加以下行 <display-name>messenger</display-name>

现在试试你的服务 http://localhost:8080/messenger/myresource

Answer 2

在学习该教程时，我也遇到了同样的问题，尝试了几件事，但是它不起作用。最后，当我将版本降级到2.6（部分测试和错误）时，它显示“ Git it”作为响应。我最初为Jersey原型选择了最新版本3.0.0-M6。

Answer 3

我遇到了类似的问题，意识到Jersey 3.0.0-M6和Tomcat 9不兼容。

原因-> Tomcat 9使用javax.servlet.Filter。雅加达EE 9的一部分Jersey 3.x依赖于基于雅加达的API软件包。 jakarta.servlet.Filter在Tomcat 10中可用。

解决方案->下载Tomcat 10并使用它。或在Tomcat 9或更低版本中使用Jersey 2.X版。

我个人将Jersey 2.16与Tomcat 9一起使用，并且对我有用。

Answer 4

<强>更新

我尝试在Jetty上部署我的应用程序，方法是将以下插件添加到pom.xml中的build部分。

<plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>maven-jetty-plugin</artifactId>
    <version>6.1.10</version>
</plugin>

然后从终端运行mvn jetty:run。现在，我可以在http://localhost:8080/messenger/webapi/myresource成功访问我的网络应用。它按预期返回Got it!。

所以，这肯定是我将它部署到tomcat的方式的问题。我有兴趣进一步调试tomcat问题，如果有人有一些指针。

在Eclipse中

4 个答案: