在JSP'中重复；s包括指令

这段代码不是真实的，但更简单，并显示了问题所在

假设我有第一个名为 Base.jsp

<%!
  class Base {
    public String Parm0 = "";
    public String Parm1 = "";

    Base () {
      PrintMessage("Base Created!!");
    }
  }
  javax.servlet.jsp.JspWriter Out;
  void SetJspWriter(javax.servlet.jsp.JspWriter out) {
    Out = out;
  }

  void PrintMessage(String Msg) {
    try {
      Out.print("<P style=\"color:rgb(255,0,0)\">"+Msg+"</P>");
    }
    catch (Exception e) {}
  }
%>

<%@ include file="Base.jsp" %>
<%!
  class File0 {
    public Base MyBase;
    File0 () {
      MyBase = new Base();
      PrintMessage("Based Used!!");
    }
  }
%>

<%@ include file="Base.jsp" %>
<%@ include file="Fil0.jsp" %>
<%!
  class File1 {
    public Base MyBase;
    public File0 MyFil0;
    File1 () {
      MyBase = new Base();
      MyFil0 = new File0();
      PrintMessage("Based and Fil0 Created!!");
    }
  }
%>
<%
  SetJspWriter(out);
  File1 MyFil1 = new File1();
%>

现在我有了第二个使用基本文件的文件： Fil0.jsp

<%!
  class Base {
    public String Parm0 = "";
    public String Parm1 = "";

    Base () {
      PrintMessage("Base Created!!");
    }
  }
  javax.servlet.jsp.JspWriter Out;
  void SetJspWriter(javax.servlet.jsp.JspWriter out) {
    Out = out;
  }

  void PrintMessage(String Msg) {
    try {
      Out.print("<P style=\"color:rgb(255,0,0)\">"+Msg+"</P>");
    }
    catch (Exception e) {}
  }
%>

<%@ include file="Base.jsp" %>
<%!
  class File0 {
    public Base MyBase;
    File0 () {
      MyBase = new Base();
      PrintMessage("Based Used!!");
    }
  }
%>

<%@ include file="Base.jsp" %>
<%@ include file="Fil0.jsp" %>
<%!
  class File1 {
    public Base MyBase;
    public File0 MyFil0;
    File1 () {
      MyBase = new Base();
      MyFil0 = new File0();
      PrintMessage("Based and Fil0 Created!!");
    }
  }
%>
<%
  SetJspWriter(out);
  File1 MyFil1 = new File1();
%>

现在我有了第三个使用基本文件的文件： Fil1.jsp

<%!
  class Base {
    public String Parm0 = "";
    public String Parm1 = "";

    Base () {
      PrintMessage("Base Created!!");
    }
  }
  javax.servlet.jsp.JspWriter Out;
  void SetJspWriter(javax.servlet.jsp.JspWriter out) {
    Out = out;
  }

  void PrintMessage(String Msg) {
    try {
      Out.print("<P style=\"color:rgb(255,0,0)\">"+Msg+"</P>");
    }
    catch (Exception e) {}
  }
%>

<%@ include file="Base.jsp" %>
<%!
  class File0 {
    public Base MyBase;
    File0 () {
      MyBase = new Base();
      PrintMessage("Based Used!!");
    }
  }
%>

<%@ include file="Base.jsp" %>
<%@ include file="Fil0.jsp" %>
<%!
  class File1 {
    public Base MyBase;
    public File0 MyFil0;
    File1 () {
      MyBase = new Base();
      MyFil0 = new File0();
      PrintMessage("Based and Fil0 Created!!");
    }
  }
%>
<%
  SetJspWriter(out);
  File1 MyFil1 = new File1();
%>

正如你所看到的。。。此代码将生成如下消息：

重复字段Fil1\u jsp.Out

在Fil1\u jsp类型中复制方法PrintMessage（字符串）

<%!
  class Base {
    public String Parm0 = "";
    public String Parm1 = "";

    Base () {
      PrintMessage("Base Created!!");
    }
  }
  javax.servlet.jsp.JspWriter Out;
  void SetJspWriter(javax.servlet.jsp.JspWriter out) {
    Out = out;
  }

  void PrintMessage(String Msg) {
    try {
      Out.print("<P style=\"color:rgb(255,0,0)\">"+Msg+"</P>");
    }
    catch (Exception e) {}
  }
%>

<%@ include file="Base.jsp" %>
<%!
  class File0 {
    public Base MyBase;
    File0 () {
      MyBase = new Base();
      PrintMessage("Based Used!!");
    }
  }
%>

<%@ include file="Base.jsp" %>
<%@ include file="Fil0.jsp" %>
<%!
  class File1 {
    public Base MyBase;
    public File0 MyFil0;
    File1 () {
      MyBase = new Base();
      MyFil0 = new File0();
      PrintMessage("Based and Fil0 Created!!");
    }
  }
%>
<%
  SetJspWriter(out);
  File1 MyFil1 = new File1();
%>

如何解决这个错误 在此之前，我需要将Base包含在两个文件中：File0和File1。 和File1有Base和File0

---

编译器找到两个声明

尝试插入以下行：

javax.servlet.jsp.JspWriter Out

仅在最后一个文件

Fil1.jsp

中，我认为使用includes实际上多次声明同一对象

另外，类

File1

中有

File0（）

构造函数

此外，由于您在File0.jsp中包含Base.jsp，然后在File1.jsp中同时包含Base.jsp和File0.jsp，因此实际上您已经包含Base.jsp两次了

---

如果你想确切地看到发生了什么，请查找编译好的jsp：你的jsp文件被编译成

.java

，通常可以在tomcat

/work

文件夹下找到，在linux中，它类似于：

/usr/local/tomcat/work/Catalina/localhost/\uu/org/apache/jsp

/p>，这很好，因为这不是我真正的答案：）对不起，我正在寻找如何管理includes指令，也许还有其他替代方法，或者指出相同代码的多样性……@Anita我在上面的回答中包含了一条关于includes的评论。