Java 如何在jsp中使用jFreechart实现饼图？

可能重复：

请有人能帮我吗

提前感谢。

编译时，请检查DefaultPieDataset类是否存在

`DefaultPieDataset` cannot be resolved to a type
30:         out.println(e);

将JSP编译为servlet时，需要解决编译时错误。此时，找不到此类。请检查jar文件是否确实存在此类文件。

1-您使用的IDE是什么

2-首先，您应该尝试清理和构建，然后运行

3-确保类路径

4-为了以防万一，您可以将JAR复制到Apachetomcat lib目录

5-如果一切正常，请确保您的库JAR可能已损坏，因此重新下载或其未正确包含或根本不包含；确保包含jar及其所有类

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我想是的，那么你应该对此负责 这些是专门为eclipse设计的

我更喜欢。它们支持饼图。见演示

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这是一个免费的jQuery库，允许您创建与图像生成相比的交互式图表

我的项目中没有DefaultPieDataset类。仅使用2个jar文件，我认为这已经在jar文件中定义。检查jar文件中是否存在此类文件。如果jar文件中不存在此类文件，则在编译过程中，jsp编译器可能无法解析依赖项。一种快速的方法是，在IDE中，可以对此进行检查。我认为是这样，那么您应该对此进行检查

6 Jun, 2012 10:03:12 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP: 

An error occurred at line: 33 in the jsp file: /pages/pieChart.jsp
DefaultPieDataset cannot be resolved to a type
30:         out.println(e);
31: 
32:     } */
33:     DefaultPieDataset pieDataset = new DefaultPieDataset();
34:     pieDataset.setValue("JavaWorld", new Integer(75));
35:     pieDataset.setValue("Other", new Integer(25));
36:     JFreeChart chart = ChartFactory.createPieChart


An error occurred at line: 33 in the jsp file: /pages/pieChart.jsp
DefaultPieDataset cannot be resolved to a type
30:         out.println(e);
31: 
32:     } */
33:     DefaultPieDataset pieDataset = new DefaultPieDataset();
34:     pieDataset.setValue("JavaWorld", new Integer(75));
35:     pieDataset.setValue("Other", new Integer(25));
36:     JFreeChart chart = ChartFactory.createPieChart


Stacktrace:
    at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92)
    at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
    at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:439)
    at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
    at org.apache.jasper.compiler.Compiler.compile(Compiler.java:334)
    at org.apache.jasper.compiler.Compiler.compile(Compiler.java:321)
    at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:592)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)
    at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)
    at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)
    at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:381)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.saveworks.application.AdminAuthenticationFilter.doFilter(AdminAuthenticationFilter.java:74)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:662)

`DefaultPieDataset` cannot be resolved to a type
30:         out.println(e);