Java中的GAE Restful Web服务 [英] GAE Restful Web Service in Java
本文介绍了Java中的GAE Restful Web服务的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想在Java中为Google App Engine开发宁静的Web服务.我正在使用的工具是
I want to develop restful web service in java for google app engine. the tools i am using are
Eclipse Kepler Service Release 2 (Build id: 20140224-0627)
Google AppEngine Java SDK 1.9.2
我使用了许多版本的Jersey，例如1.8、1.5等.如果我在本地服务器上运行项目，则可以正常工作，但是当我将其部署在google app引擎上时，我可以打开欢迎网页，但无法访问网络服务.
i have used many versions of Jersey, e.g. 1.8, 1.5 etc. if i run the project on local server it works fine but when i deploy it on the google app engine i can able to open the welcome web page but can't able to access web service.
/WillItPlayInJava 链接，GAE支持Jersey 1.5，但是当我在项目中导入这些jar文件时，我无法将其部署在GAE上.
as mentioned in https://code.google.com/p/googleappengine/wiki/WillItPlayInJava link, GAE support Jersey 1.5 but when i import those jars files in my project i can't able to deploy it on GAE.
我不知道应该使用哪个版本的Jersey Google AppEngine Java SDK 1.9.2 还是我应该使用其他版本的SDK.
i don't know which version of Jersey should i use with Google AppEngine Java SDK 1.9.2 or should i use another version of SDK.
我的web.xml文件
my web.xml file
<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
<display-name>com.cit.cittracker</display-name>
<servlet>
<servlet-name>Sample Web Service</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>com.cit.cittracker</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.config.feature.DisableWADL</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Sample Web Service</servlet-name>
<url-pattern>/restservices/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>
我的网络服务课程
package com.aakib.sample;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.PathParam;
@Path("/hello")
public class SampleHello {
/*This method is called if TEXT_PLAIN is requested*/
@GET
@Produces(MediaType.TEXT_PLAIN)
public String sayPlainTextHello() {
return "Hello Jersey" + "(In Text Format)";
}
/*This method is called if XML is requested*/
@GET
@Produces(MediaType.TEXT_XML)
public String sayXMLHello() {
return "<?xml version=\"1.0\"?>" + "<hello>Hello Jersey</hello>"
+ "<format>XML</format>";
}
/*This method is called if HTML is requested*/
@GET
@Produces(MediaType.TEXT_HTML)
public String sayHtmlHello() {
return "<html> " + "<title>" + "Hello Jersey" + "</title>"
+ "<body><h1>" + "Hello Jersey" + "</h1><h2>In HTML Format<h2></body>" + "</html> ";
}
/*This method is called if HTML is requested and have two parameters*/
@GET
@Path("{name}")
@Produces(MediaType.TEXT_HTML)
public String sayHtmlHelloWith1Param(@PathParam("name") String vName) {
return "<html> " + "<title>" + "Hello Jersey" + "</title>"
+ "<body><h1>Hello " + vName + "</h1><h2>In HTML Format</h2>" +
"<h3>1 Value Passed</h3>" + "</body>" + "</html> ";
}
/*This method is called if HTML is requested and have two parameters*/
@GET
@Path("{name}/{surname}")
@Produces(MediaType.TEXT_HTML)
public String sayHtmlHelloWith2Param(@PathParam("name") String vName, @PathParam("surname") String vSurname) {
return "<html> " + "<title>" + "Hello Jersey" + "</title>"
+ "<body><h1>Hello " + vName + " " + vSurname + "</h1><h2>In HTML Format</h2>" +
"<h3>2 Value Passed</h3>" + "</body>" + "</html> ";
}
}
当我尝试使用Jersey 2.5&泽西岛1.17，我在本地服务器上收到错误消息，
when i tried with Jersey 2.5 & Jersey 1.17 i got the error on local server as
Apr 12, 2014 2:10:45 AM java.util.prefs.WindowsPreferences <init>
WARNING: Could not open/create prefs root node Software\JavaSoft\Prefs at root 0x80000002. Windows RegCreateKeyEx(...) returned error code 5.
Apr 12, 2014 2:10:47 AM com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
INFO: Successfully processed B:\Programming\Java EE\CIT Tracker Web Service\war\WEB-INF/appengine-web.xml
Apr 12, 2014 2:10:47 AM com.google.apphosting.utils.config.AbstractConfigXmlReader readConfigXml
INFO: Successfully processed B:\Programming\Java EE\CIT Tracker Web Service\war\WEB-INF/web.xml
Apr 12, 2014 2:10:47 AM com.google.appengine.tools.development.SystemPropertiesManager setSystemProperties
INFO: Overwriting system property key 'java.util.logging.config.file', value 'C:\Program Files (x86)\Google AppEngine Java SDK 1.9.2\config\sdk\logging.properties' with value 'WEB-INF/logging.properties' from 'B:\Programming\Java EE\CIT Tracker Web Service\war\WEB-INF\appengine-web.xml'
Apr 12, 2014 2:10:47 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
Apr 12, 2014 2:10:47 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: jetty-6.1.x
Apr 12, 2014 2:10:48 AM com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
com.cit.cittracker
Apr 12, 2014 2:10:48 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed CIT Tracker WebService: java.lang.IncompatibleClassChangeError: Implementing class
Apr 12, 2014 2:10:48 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed com.google.appengine.tools.development.DevAppEngineWebAppContext@7adb5354{/,B:\Programming\Java EE\CIT Tracker Web Service\war}: java.lang.IncompatibleClassChangeError: Implementing class
Apr 12, 2014 2:10:48 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: failed JettyContainerService$ApiProxyHandler@4c73cedb: java.lang.IncompatibleClassChangeError: Implementing class
Apr 12, 2014 2:10:48 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: Error starting handlers
java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:216)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.sun.jersey.api.core.ScanningResourceConfig.init(ScanningResourceConfig.java:79)
at com.sun.jersey.api.core.PackagesResourceConfig.init(PackagesResourceConfig.java:104)
at com.sun.jersey.api.core.PackagesResourceConfig.<init>(PackagesResourceConfig.java:78)
at com.sun.jersey.api.core.PackagesResourceConfig.<init>(PackagesResourceConfig.java:89)
at com.sun.jersey.spi.container.servlet.WebComponent.createResourceConfig(WebComponent.java:696)
at com.sun.jersey.spi.container.servlet.WebComponent.createResourceConfig(WebComponent.java:674)
at com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:203)
at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:374)
at com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:557)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:440)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:263)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:685)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
at org.mortbay.jetty.Server.doStart(Server.java:224)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:254)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:305)
at com.google.appengine.tools.development.AutomaticInstanceHolder.startUp(AutomaticInstanceHolder.java:26)
at com.google.appengine.tools.development.AbstractModule.startup(AbstractModule.java:79)
at com.google.appengine.tools.development.Modules.startup(Modules.java:97)
at com.google.appengine.tools.development.DevAppServerImpl.doStart(DevAppServerImpl.java:255)
at com.google.appengine.tools.development.DevAppServerImpl.access$000(DevAppServerImpl.java:47)
at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:213)
at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:211)
at java.security.AccessController.doPrivileged(Native Method)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:211)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:277)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
at com.google.appengine.tools.development.DevAppServerMain.run(DevAppServerMain.java:219)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:210)
Apr 12, 2014 2:10:48 AM com.google.apphosting.utils.jetty.JettyLogger info
INFO: Started SelectChannelConnector@127.0.0.1:8888
Apr 12, 2014 2:10:48 AM com.google.appengine.tools.development.AbstractModule startup
INFO: Module instance default is running at http://localhost:8888/
Apr 12, 2014 2:10:48 AM com.google.appengine.tools.development.AbstractModule startup
INFO: The admin console is running at http://localhost:8888/_ah/admin
Apr 12, 2014 2:10:48 AM com.google.appengine.tools.development.DevAppServerImpl doStart
INFO: Dev App Server is now running
当我尝试在浏览器中打开时说
and when i try to open in browser it says
HTTP ERROR: 404
Problem accessing /. Reason:
NOT_FOUND
Powered by Jetty://
推荐答案
错误消息
java.lang.IncompatibleClassChangeError: Implementing class
应该是线索-尽管它并不太有用，但这可能意味着该应用程序已在类路径的某个位置成功加载了一个类及其接口，但是它们不兼容.
shoud be the clue - though it isn't too helpful, it perhaps implies that somewhere on your classpath the application has managed to load a class and its interface but they are incompatible.
在错误日志中更高一点:
A little higher up in the error log:
WARNING: failed com.google.appengine.tools.development.DevAppEngineWebAppContext@7adb5354{/,B:\Programming\Java EE\CIT Tracker Web Service\war}: java.lang.IncompatibleClassChangeError: Implementing class
看起来它正在使用本地Windows驱动器上的路径，其中带有空格-请勿在您的路径中使用空格，Microsoft允许Windows95使用它，此后一直引起问题，并且不指定路径到部署时的本地驱动器-它需要相对于应用程序.
looks like it is using a path on a local windows drive, with a space in it - don't use spaces in your paths, Microsoft allowed it from Windows95 and it's caused problems ever since, and don't specify a path to your local drive on deployment - it needs to be application-relative.
希望这会有所帮助，抱歉，不要更具体.
Hope this helps, sorry to not be more specific.
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