java - Maven导入的Gson类部署在JSP和Servlet Java Web上找不到
问题描述
我通过 maven 导入了 Gson,其代码为
<?xml version="1.0" encoding="UTF-8"?>
<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>org.example</groupId>
<artifactId>HerbTea</artifactId>
<version>1.0-SNAPSHOT</version>
<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
<dependencies>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.4.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.4.0</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
但是,当我在 JSP sevlet 程序上运行我的程序时,我收到
java.lang.NoClassDefFoundError: com/google/gson/Gson
我不知道为什么。
您可以在此处查看错误报告
HTTP Status 500 – Internal Server Error
________________________________________
Type Exception Report
Message An exception occurred processing [/outcome.jsp] at line [21]
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
org.apache.jasper.JasperException: An exception occurred processing [/outcome.jsp] at line [21]
18: <% WindowDisplay windowDisplay = (WindowDisplay) request.getSession().getAttribute("windowDisplay");
19: System.out.println(session.getAttribute(reqSymptomParamKey));
20: windowDisplay.getRecipeDisplay();
21: List<Recipe> a = windowDisplay.getRecipeDisplay().retrieveCorrespondingRecipe((List<String>) session.getAttribute(reqSymptomParamKey));
22: for (Recipe i : windowDisplay.getRecipeDisplay().retrieveCorrespondingRecipe((List<String>) session.getAttribute(reqSymptomParamKey))) {%>
23: <p1>name:<%=i.getName()%> </p1>
24: <p1>Corresponding Symptom: <%=i.getSymptomNameList()%></p1>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:617)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:499)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
com.web.servlet.ServerServlet.doPost(ServerServlet.java:60)
javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Root Cause
javax.servlet.ServletException: java.lang.NoClassDefFoundError: com/google/gson/Gson
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:909)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:838)
org.apache.jsp.outcome_jsp._jspService(outcome_jsp.java:178)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
com.web.servlet.ServerServlet.doPost(ServerServlet.java:60)
javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Root Cause
java.lang.NoClassDefFoundError: com/google/gson/Gson
根据调试器出现问题的行是这一行,因为没有找到 Gson 包中的任何类:
GsonBuilder gsonBuilder = new GsonBuilder();
有人可以帮我解决这个java.lang.NoClassDefFoundError: com/google/gson/Gson
问题吗?
解决方案
我最终自己找到了问题的答案。感谢那些帮助我编辑问题的人。
问题是我没有将 Maven libaray 添加到工件中。
解决方案将进入 Intellij 中的 Project Structure->Artifacts->Output layout 并单击“Available Elements”面板下相应的 Maven 导入 jar 以将该 Gson libaray jar 添加到工件中。
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