java - Servlet 无法识别 JSON？

Question

我收到以下跟踪轨迹，但不确定原因:

SEVERE: Servlet.service() for servlet [BuddyController] in context with path [/gbserver] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: org.apache.commons.lang.exception.NestableRuntimeException
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
    at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2904)
    at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1173)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1681)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    at com.mathanv.gb.dao.BuddyDao.registerBuddy(BuddyDao.java:50)
    at com.mathanv.gb.controller.BuddyController.doPost(BuddyController.java:53)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:680)

上面的跟踪轨迹是由以下代码生成的:

JSONObject response = new JSONObject();

我有以下结构:

知道为什么我收到错误吗？

Answer 1

您需要将 Commons Lang 包含在您的库中；显然你的 JSON 库依赖于它。 (具体来说，您看到的异常是因为 org.apache.commons.lang.exception.NestableRuntimeException — 请参阅 http://commons.apache.org/proper/commons-lang//javadocs/api-2.6/org/apache/commons/lang/exception/NestableRuntimeException.html — 不在您的类路径中。)