Question

我想创建一个REST服务器。

我添加了maven依赖项，我的pom.xml看起来像这样：

<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>abptc_server</groupId>
    <artifactId>abptc_server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.0</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>

            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-server</artifactId>
            <version>9.1.3.v20140225</version>
        </dependency>

        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-servlet</artifactId>
            <version>9.1.3.v20140225</version>
        </dependency>

        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>jsr311-api</artifactId>
            <version>1.1.1</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-core</artifactId>
            <version>1.18.1</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-server</artifactId>
            <version>1.18.1</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-client</artifactId>
            <version>1.18.1</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-servlet</artifactId>
            <version>1.18.1</version>
        </dependency>

        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-json</artifactId>
            <version>1.18.1</version>
        </dependency>

    </dependencies>
</project>

我添加了maven-assembly-plugin，因为我想要一个jar，我可以执行：

java -cp target/abptc_server-0.0.1-SNAPSHOT-jar-with-dependencies.jar server.MinimalServerRest

当我在eclipse中运行服务器时，它运行良好，但是当我执行jar时，服务器在一个REST请求后失败：GET http://localhost:9999/employee/getEmployee

错误：

2014-03-20 11:40:46.996:INFO::main: Logging initialized @576ms
2014-03-20 11:40:47.133:INFO:oejs.Server:main: jetty-9.1.z-SNAPSHOT
2014-03-20 11:40:47.176:INFO:oejsh.ContextHandler:main: Started o.e.j.s.ServletContextHandler@7dbe444b{/,null,AVAILABLE}
2014-03-20 11:40:47.194:INFO:oejs.ServerConnector:main: Started ServerConnector@6bb9db06{HTTP/1.1}{0.0.0.0:9999}
2014-03-20 11:40:47.194:INFO:oejs.Server:main: Started @777ms
márc. 20, 2014 11:40:53 DE com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
  rest
márc. 20, 2014 11:40:53 DE com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Root resource classes found:
  class rest.EmployeeSvc
  class rest.StudentSvc
márc. 20, 2014 11:40:53 DE com.sun.jersey.api.core.ScanningResourceConfig init
INFO: No provider classes found.
márc. 20, 2014 11:40:54 DE com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.18.1 02/19/2014 03:28 AM'
márc. 20, 2014 11:40:54 DE com.sun.jersey.spi.container.ContainerResponse write
SEVERE: A message body writer for Java class dto.Employee, and Java type class dto.Employee, and MIME media type application/json was not found.
The registered message body writers compatible with the MIME media type are:
*/* ->
  com.sun.jersey.core.impl.provider.entity.FormProvider
  com.sun.jersey.core.impl.provider.entity.StringProvider
  com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
  com.sun.jersey.core.impl.provider.entity.FileProvider
  com.sun.jersey.core.impl.provider.entity.InputStreamProvider
  com.sun.jersey.core.impl.provider.entity.DataSourceProvider
  com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$General
  com.sun.jersey.core.impl.provider.entity.ReaderProvider
  com.sun.jersey.core.impl.provider.entity.DocumentProvider
  com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider
  com.sun.jersey.core.impl.provider.entity.SourceProvider$SourceWriter
  com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General

márc. 20, 2014 11:40:54 DE com.sun.jersey.spi.container.ContainerResponse logException
SEVERE: Mapped exception to response: 500 (Internal Server Error)
javax.ws.rs.WebApplicationException: com.sun.jersey.api.MessageException: A message body writer for Java class dto.Employee, and Java type class dto.Employee, and MIME media type application/json was not found.

    at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:284)
    at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1510)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419)
    at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409)
    at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:540)
    at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:715)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:711)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:219)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1112)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:479)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1046)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
    at org.eclipse.jetty.server.Server.handle(Server.java:462)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:281)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:232)
    at org.eclipse.jetty.io.AbstractConnection$1.run(AbstractConnection.java:505)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536)
    at java.lang.Thread.run(Thread.java:744)
Caused by: com.sun.jersey.api.MessageException: A message body writer for Java class dto.Employee, and Java type class dto.Employee, and MIME media type application/json was not found.

    ... 24 more

我搜索了SO的答案：

https://stackoverflow.com/a/12427046/598280和https://stackoverflow.com/a/6027161/598280我已添加jersey-json依赖性。

https://stackoverflow.com/a/11936282/598280我没有web.xml并且服务器运行良好，当我在eclipse中执行时，问题出在maven上。

https://stackoverflow.com/a/13108540/598280同样。

根据Mark Needham blog，我的服务器类看起来很好：

ServletHolder sh = new ServletHolder(ServletContainer.class);
sh.setInitParameter("com.sun.jersey.config.property.resourceConfigClass", "com.sun.jersey.api.core.PackagesResourceConfig");

// Set the package where the services reside
sh.setInitParameter("com.sun.jersey.config.property.packages", "rest");
sh.setInitParameter("com.sun.jersey.api.json.POJOMappingFeature", "true");

Server server = new Server(9999);
ServletContextHandler context = new ServletContextHandler(server, "/", ServletContextHandler.SESSIONS);
context.addServlet(sh, "/*");
server.start();
server.join();

我该如何解决这个问题？

更新

我的打包罐看起来像这样： jar

我没有检查所有依赖性（它有23个个体的依赖性），但从这里看起来很好。我应该检查所有吗？

这是maven clean install输出：http://pastebin.com/Whk2qr2i

Answer 1

嗯，这种方法的问题在于，如果多个JARS具有相同的文件，则会被覆盖。例如。所有这些罐子可能都有META-INF/MANIFEST.MF个文件，但实际上只有一个。这可能适用于其他文件。这可能会导致奇怪的行为

我会尝试使用maven将它们构建为单独的JARS，然后尝试运行并查看是否有效。您可以使用程序集插件构建一个ZIP，其中包含您的应用程序JAR和lib文件夹中的所有JAR文件，以及运行它的脚本。例如。 zip的内容如下：

abptcserver/
    lib/
        dependency1.jar
        dependency2.jar
        dependency3.jar
    abptcserver.jar
    run.sh
    run.bat

然后，您可以配置shell和批处理脚本，以使用类路径上的lib目录中的所有JARS运行服务器。我想你会以这种方式获得更少的意外行为，它也更强大，更便于用户运行

Answer 2

使用maven的shade插件而不是程序集插件。

它不会覆盖类，即使在不同的jar中存在相同的名称，也会解决此问题。

使用Maven-assembly打包单罐

更新

2 个答案: