Servlet中:request.setAttribute("styles",result1);jsp中:
<html>
<body>
<%@ page language="java" %>
<%@ page import="java.util.*" %>
<%@ page contentType="text/html;charset=GBK"%><%
List styles =(List)request.getAttribute("styles");
Iterator it=styles.iterator();
while (it.hasNext()){
out.print("<br>"+it.next());
}
%></body>
</html>jsp中仅有上述代码时OK,但是加入了jfrechart生成柱形图的代码,提示如下错误:类型 list有歧义
解决方案 »
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<%@ page import="java.util.*" %><%@ page import="org.jfree.chart.ChartFactory,
org.jfree.chart.JFreeChart,
org.jfree.chart.plot.PlotOrientation,
org.jfree.chart.servlet.ServletUtilities,
org.jfree.chart.axis.*,
org.jfree.chart.plot.CategoryPlot,
org.jfree.ui.ApplicationFrame,
org.jfree.ui.RefineryUtilities,
org.jfree.data.category.CategoryDataset,
org.jfree.chart.renderer.category.BarRenderer,
java.io.*,
java.awt.*,
org.jfree.chart.*,
org.jfree.data.general.*,
java.util.Locale,org.jfree.chart.*,
org.jfree.chart.ChartFrame,
org.jfree.data.general.DefaultPieDataset,
java.util.Locale,org.jfree.chart.*,
org.jfree.data.category.DefaultCategoryDataset"%>
<%@ page import="java.awt.*" %>
<%@ page import="javax.swing.JPanel" %>
<%@ page import="java.io.OutputStream" %>
<%@ page import="org.jfree.chart.title.TextTitle" %>
<%@ page import="org.jfree.chart.title.LegendTitle" %>
<%@ page import="org.jfree.chart.plot.PiePlot" %>
org.apache.jasper.JasperException: Unable to compile class for JSP: An error occurred at line: 35 in the jsp file: /result1.jsp
The type List is ambiguous
32:
33:
34: <%
35: java.util.List styles =(List)request.getAttribute("styles");
36: Iterator it=styles.iterator();
37: while (it.hasNext()){
38: out.print("<br>"+it.next());仍然不可!!
如何将it.next()的值转换成Number型和字符串型??用于Frecchart使用dataset.addValue(30, "6月", "苹果" );java.util.List styles=(java.util.List)request.getAttribute("styles");
Iterator it=styles.iterator();
while (it.hasNext())
{
out.print("<br>"+it.next());
}
加泛型:Iterator<String> it=styles.iterator();
ava.util.List Qty =(java.util.List)request.getAttribute("Qty1");
Iterator q=Qty.iterator();
java.util.List Pdt =(java.util.List)request.getAttribute("Pdt1");
Iterator p=Pdt.iterator();String title="ECO数量";
DefaultCategoryDataset dataset = new DefaultCategoryDataset();
while (q.hasNext())
{dataset.addValue((Integer)q.next(), "6月",(String)p.next() );
}构建时无错误,可是提交时报错:
org.apache.jasper.JasperException: Exception in JSP: /result1.jsp:5451: String title="ECO数量";
52: DefaultCategoryDataset dataset = new DefaultCategoryDataset();
53: while (q.hasNext())
54: {dataset.addValue((Integer)q.next(), "6月", "安全产品线");
55: }
56:
57: //dataset.addValue(30, "6月", "安全产品线");
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
com.example.web.ECSelect.doPost(ECSelect.java:49)
javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
修改成:
java.util.List Pdt =(java.util.List)request.getAttribute("Pdt1");
Iterator <String> p=Pdt.iterator();
直接前面带“X”
搞定了,多谢各位!int n=Integer.parseInt((String)q.next());
String a=(String)p.next();业务强相关的一个小任务完成~~庆祝
请教!!请教!!