我有一个 Controller 和一个gsp。我继续尝试构建项目，但在我的gsp上遇到了问题。

它告诉我“当前作用域已经包含一个名称为它的变量”

<html> 
  <head> 
    <title>Book Collector</title> 
    <meta name="layout" content="main" /> 
  </head> 
  <body> 
    <h1>Book Editor</h1> 
    <table> 
      <tr> 
        <th>Book Name</th> 
        <th>Author</th> 
        <th>Page Number</th> 
        <th>Vendor</th> 
        <th>Date Scanned</th> 
        <th>Date Read</th> 
      </tr> 
      <% bookList.each { it -> %> 
      <tr> 
        <td><%= it.bookName %></td>    //this is where the error starts 
        <td><%= it.author %></td>      //error (it) 
        <td><%= it.pageNumber %></td>  //error (it) 
        <td><%= it.lastScan %></td>    //error (it) 
        <td><%= it.lastRead %></td>    //error (it) 
        <% } %> 
      </tr> 
    </table> 
  </body> 
</html> 

请您参考如下方法:

http://www.grails.org/Views+and+Layouts

<html> 
<head> 
    <title>Book list</title> 
</head> 
<body> 
<h1>Book list</h1> 
<table> 
    <tr> 
        <th>Title</th> 
         <th>Author</th> 
    </tr> 
    <g:each in="${books}"> 
        <tr> 
             <td>${it.title}</td> 
             <td>${it.author}</td> 
        </tr> 
    </g:each> 
</table> 
</body> 
</html>