简单的JAVABEAN问题？！

Question

public class price 
{
private static Hashtable things = new Hashtable();
public void getThings(String id)
{
things.put("1","cup");
things.put("2","内存");
things.put("3","主板");
things.put("4","显卡");
things.put("5","显示器"); return things.get(id).toString();
}
}
改：
public class price 
{
private static Hashtable things = new Hashtable();
public String  getThings(String id)
{
things.put("1","cup");
things.put("2","内存");
things.put("3","主板");
things.put("4","显卡");
things.put("5","显示器"); return things.get(id).toString();
}
}

Answer 1

从报错信息上看，好像是找不到类不过我觉得你的getThings方法是不是也有点问题？每次调用这个方法，都要往哈希表添加信息，那么第二次的时候是否就会重现key值重复了？（当然，如果你在该页面只调用一次该方法是不会出现key值重复的，但调用对次应该就会出现的）我觉得把哈希表信息初始化放在构造函数或setThings方法上比较好

Answer 2

在classpath变量里把price所在的目录添加进去再重新编译试试，如目录结构为：C:\java\test\com\bean\price.java
就在classpath里加入：C:\java\test

Answer 3

应该是找不到类
在运行的使用指定classpath

Answer 4

public void ....{
   ...
   return things.get(id).toString();
}
这个编译能通过？你把这个price.class放哪里了？

Answer 5

package  com.bean; 
import java.util.*;
import java.io.*;
public class price 
{
private static Hashtable things = new Hashtable();
public String getThings(String id)
{
things.put("1","cup");
things.put("2","内存");
things.put("3","主板");
things.put("4","显卡");
things.put("5","显示器");
System.out.println(things.get(id).toString());
}
}
改成这样后出现编译错误：missing return statement

Answer 6

你写了返回类型却没有写返回值啊！
public String getThings(String id)
{
things.put("1","cup");
things.put("2","内存");
things.put("3","主板");
things.put("4","显卡");
things.put("5","显示器");
System.out.println(things.get(id).toString());
}
"return"何在？

Answer 7

package  com.bean; 
import java.util.*;
import java.io.*;
public class price 
{
private static Hashtable things = new Hashtable(); public String getThings(String id)
{
things.put("1","cup");
things.put("2","内存");
things.put("3","主板");
things.put("4","显卡");
things.put("5","显示器");

return things.get(id).toString();
}

}
改成这样还是出显：
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: com/bean/price (wrong name: price)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:244)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause java.lang.NoClassDefFoundError: com/bean/price (wrong name: price)
java.lang.ClassLoader.defineClass0(Native Method)
java.lang.ClassLoader.defineClass(ClassLoader.java:502)
java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1634)
org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:860)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1307)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1189)
org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1214)
org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1116)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2213)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2219)
org.apache.jasper.compiler.Node$Root.accept(Node.java:456)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2163)
org.apache.jasper.compiler.Generator.generate(Generator.java:3272)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:244)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:470)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

Answer 8

好了，我重新启动了TOMCAT！给分了