Question

Servlet execution threw an exception 怎解决？

HTTP Status 500 - Servlet execution threw an exception
type Exception report
message Servlet execution threw an exception
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Servlet execution threw an exception
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause
java.lang.NoClassDefFoundError: com/google/gson/Gson
com.yg.examle.JsonServlet.doPost(JsonServlet.java:93)
com.yg.examle.JsonServlet.doGet(JsonServlet.java:37)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause
java.lang.ClassNotFoundException: com.google.gson.Gson
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1305)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1157)
com.yg.examle.JsonServlet.doPost(JsonServlet.java:93)
com.yg.examle.JsonServlet.doGet(JsonServlet.java:37)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Answer 1

缺少依赖库，
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.3.1</version>
</dependency>

Answer 2

你这个是本地的程序，还是调用别人的接口？

从请求状态Http Status 500可以知道，服务端的代码有错误。所以，如果是本地代码，你需要调试。如果是第三方接口，你需要联系接口开发人员。