freemarker自定义标签报错（七）

1、错误描述

六月 09, 2014 11:11:09 下午 freemarker.log.JDK14LoggerFactory$JDK14Logger error
严重: Template processing error: "Expression a is undefined on line 27, column 23 in tag.ftl."

Expression a is undefined on line 27, column 23 in tag.ftl.
The problematic instruction:
----------
==> ${a} [on line 27, column 21 in tag.ftl]
 in user-directive tag [on line 25, column 6 in tag.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression a is undefined on line 27, column 23 in tag.ftl.
	at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:125)
	at freemarker.core.Expression.getStringValue(Expression.java:118)
	at freemarker.core.Expression.getStringValue(Expression.java:93)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.visit(Environment.java:406)
	at freemarker.core.BodyInstruction.accept(BodyInstruction.java:93)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Macro$Context.runMacro(Macro.java:172)
	at freemarker.core.Environment.visit(Environment.java:614)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:106)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.process(Environment.java:199)
	at freemarker.template.Template.process(Template.java:259)
	at com.you.freemarker.FreemarkerTemplate.printFtl(FreemarkerTemplate.java:77)
	at com.you.test.freemarker.FreemarkerTest.studentPrint(FreemarkerTest.java:224)
	at com.you.test.freemarker.FreemarkerTest.testTag(FreemarkerTest.java:211)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Expression a is undefined on line 27, column 23 in tag.ftl.
The problematic instruction:
----------
==> ${a} [on line 27, column 21 in tag.ftl]
 in user-directive tag [on line 25, column 6 in tag.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression a is undefined on line 27, column 23 in tag.ftl.
	at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:125)
	at freemarker.core.Expression.getStringValue(Expression.java:118)
	at freemarker.core.Expression.getStringValue(Expression.java:93)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.visit(Environment.java:406)
	at freemarker.core.BodyInstruction.accept(BodyInstruction.java:93)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Macro$Context.runMacro(Macro.java:172)
	at freemarker.core.Environment.visit(Environment.java:614)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:106)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.process(Environment.java:199)
	at freemarker.template.Template.process(Template.java:259)
	at com.you.freemarker.FreemarkerTemplate.printFtl(FreemarkerTemplate.java:77)
	at com.you.test.freemarker.FreemarkerTest.studentPrint(FreemarkerTest.java:224)
	at com.you.test.freemarker.FreemarkerTest.testTag(FreemarkerTest.java:211)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <title>freemarker自定义标签</title>

  </head>

  <body>

	           <h1>张三，你好1</h1>
	           <h1>张三，你好2</h1>
	           <h1>张三，你好3</h1>
	           <h1>张三，你好4</h1>
	           <h1>张三，你好5</h1>
	           <h1>张三，你好6</h1>
	           <h1>张三，你好7</h1>
	           <h1>张三，你好8</h1>
	           <h1>张三，你好9</h1>
	           <h1>张三，你好10</h1>
	           <h1>张三，你好11</h1>
	           <h1>张三，你好12</h1>
	           <h1>张三，你好13</h1>
	           <h1>张三，你好14</h1>
	           <h1>张三，你好15</h1>
	           <h1>张三，你好16</h1>
	           <h1>张三，你好17</h1>
	           <h1>张三，你好18</h1>
	           <h1>张三，你好19</h1>
	           <h1>张三，你好20</h1>
	           <h1>张三，你好21</h1>
	           <h1>张三，你好22</h1>
	           <h1>张三，你好23</h1>
	           <h1>张三，你好24</h1>
	           <h1>张三，你好25</h1>
	           <h1>张三，你好26</h1>
	           <h1>张三，你好27</h1>
	           <h1>张三，你好28</h1>
	           <h1>张三，你好29</h1>
	           <h1>张三，你好30</h1>
	           <h1>张三，你好31</h1>
	           <h1>张三，你好32</h1>
	           <h1>张三，你好33</h1>
	           <h1>张三，你好34</h1>
	           <h1>张三，你好35</h1>
	           <h1>张三，你好36</h1>
	           <h1>张三，你好37</h1>
	           <h1>张三，你好38</h1>
	           <h1>张三，你好39</h1>
	           <h1>张三，你好40</h1>

         <ul>
           <li>1----45----78</li>
         </ul>
         <ul>
           <li>1----
Expression a is undefined on line 27, column 23 in tag.ftl.
The problematic instruction:
----------
==> ${a} [on line 27, column 21 in tag.ftl]
 in user-directive tag [on line 25, column 6 in tag.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression a is undefined on line 27, column 23 in tag.ftl.
	at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:125)
	at freemarker.core.Expression.getStringValue(Expression.java:118)
	at freemarker.core.Expression.getStringValue(Expression.java:93)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.visit(Environment.java:406)
	at freemarker.core.BodyInstruction.accept(BodyInstruction.java:93)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Macro$Context.runMacro(Macro.java:172)
	at freemarker.core.Environment.visit(Environment.java:614)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:106)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.process(Environment.java:199)
	at freemarker.template.Template.process(Template.java:259)
	at com.you.freemarker.FreemarkerTemplate.printFtl(FreemarkerTemplate.java:77)
	at com.you.test.freemarker.FreemarkerTest.studentPrint(FreemarkerTest.java:224)
	at com.you.test.freemarker.FreemarkerTest.testTag(FreemarkerTest.java:211)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

2、错误原因

<#macro tag>
          <#nested 45 78/>
          <#nested/>
          <#nested/>
          <#nested/>
     </#macro>

     <@tag;a,b>
         <ul>
           <li>1----${a}----${b}</li>
         </ul>
     </@tag>

nested没有全部赋值

3、解决办法

<#macro tag>
          <#nested 45 78/>
          <#nested 56 12/>
          <#nested 23 69/>
          <#nested 44 98/>
     </#macro>

     <@tag;a,b>
         <ul>
           <li>1----${a}----${b}</li>
         </ul>
     </@tag>

结果：

<ul>
           <li>1----45----78</li>
         </ul>
         <ul>
           <li>1----56----12</li>
         </ul>
         <ul>
           <li>1----23----69</li>
         </ul>
         <ul>
           <li>1----44----98</li>
         </ul>

通过这种参数可以获取自定义指令中的变量