在Servlet中使用org.json会导致java.lang.ClassNotFoundException:org.json.jsoneException
我正试图开发一个servlet来发送一些JSON对象,但有几个例外。我相信我需要添加一些jar文件,但我不确定是哪个。 以下是doGet方法以及我导入的所有方法:在Servlet中使用org.json会导致java.lang.ClassNotFoundException:org.json.jsoneException,java,json,servlets,Java,Json,Servlets,我正试图开发一个servlet来发送一些JSON对象,但有几个例外。我相信我需要添加一些jar文件,但我不确定是哪个。 以下是doGet方法以及我导入的所有方法: import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.Ht
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONException;
import org.json.JSONObject;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("application/json");
PrintWriter out = response.getWriter();
JSONObject obj = new JSONObject();
try {
obj.put("name", "jad");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
out.println(obj.toString());
}
这是我的控制台:
SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/CarpoolServer]]
at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/CarpoolServer]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
... 7 more
Caused by: java.lang.NoClassDefFoundError: org/json/JSONException
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getDeclaredFields(Unknown Source)
at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)
at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:261)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:140)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:67)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:405)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:881)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:369)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5269)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
Caused by: java.lang.ClassNotFoundException: org.json.JSONException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1713)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1558)
... 21 more
May 03, 2013 6:16:01 PM org.apache.catalina.core.ContainerBase startInternal
SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:302)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:732)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.startup.Catalina.start(Catalina.java:684)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:456)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
May 03, 2013 6:16:01 PM org.apache.catalina.startup.Catalina start
SEVERE: Catalina.start:
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.startup.Catalina.start(Catalina.java:684)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:456)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:732)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 9 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:302)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 11 more
将
javajson.jar
添加到Eclipse的部署程序集中
@JBNizet是否推断Tomcat运行时中包含该库(json jena.jar)?请使用ctrl-shift-T并键入缺少的类名。在项目视图中找到它的jar,并确保该jar位于WEB项目中的WEB-INF/lib下。WEB-INF/lib下的所有JAR都位于webapp的编译类路径和运行时类路径中。您还可以从项目的构建路径找到jar。将其从生成路径中删除并添加到WEB-INF/lib。@凯文:绝对不是。OP已经在compiletime类路径中有了它(显然OP在没有真正理解自己在做什么的情况下篡改了IDE项目的“Build Path”属性;直接将JAR放入
/WEB-INF/lib
文件夹就足以涵盖compiletime和运行时类路径)。否则OP将无法编译servlet类。顺便说一下,它不是Jena的JSON,它只是从@Kevin:uh可用,@WebServlet
s是通过反射加载的。@KevinBowersox:这就是问题所在:OP的编译类路径中有jar,但未能将其包含在已部署应用程序的WEB-INF/lib目录中,这使得它在运行时不可用,因此出现了例外。@Jad感谢JB,他真的为我准备了这个。我认为您获得下载是因为您在响应上设置了contenttype。尝试一下,不只是为了好玩。您可能希望在测试之后将其设置回原来的设置。@Jad我假设这将用于ajax请求中,因此这应该是适当的内容类型。