Java @规则声明导致调试尝试出错
groovy JUnit测试类只有一个静态声明:Java @规则声明导致调试尝试出错,java,eclipse,groovy,junit,junit-rule,Java,Eclipse,Groovy,Junit,Junit Rule,groovy JUnit测试类只有一个静态声明: @Rule public static ErrorCollector errorCollector; 尝试在调试模式下启动测试后,将引发异常: java.lang.NullPointerException at org.junit.runners.BlockJUnit4ClassRunner.withRules(BlockJUnit4ClassRunner.java:354) at org.junit.runners.BlockJUnit4Cl
@Rule
public static ErrorCollector errorCollector;
尝试在调试模式下启动测试后,将引发异常:
java.lang.NullPointerException
at org.junit.runners.BlockJUnit4ClassRunner.withRules(BlockJUnit4ClassRunner.java:354)
at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:270)
at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
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)
在代码中的任何一行开始之前引发异常。
如果我扔掉“@Rule”字,测试运行正常(至少从一开始)
进口产品包括:
import static org.hamcrest.CoreMatchers.*;
import org.hamcrest.Matcher;
import static org.hamcrest.Matchers.*;
import org.junit.Rule;
import org.junit.rules.ErrorCollector;
import org.junit.Test;
import static org.junit.Assert.*;
import org.junit.Before;
import groovy.util.slurpersupport.NodeChild
import groovy.xml.MarkupBuilder
import groovy.xml.StreamingMarkupBuilder
import groovy.xml.XmlUtil
import org.codehaus.groovy.tools.xml.DomToGroovy
import org.joda.time.DateTime
import org.w3c.dom.Document;
import java.util.concurrent.Callable;
JUnit版本4.8.2
Eclipse版本:3.6
Java版本:1.6.41
请问我应该在哪里查找问题?正如您在上看到的,您必须创建一个实例来使用它,如下所示:
@Rule
public ErrorCollector collector= new ErrorCollector();
正如您在上所看到的,您必须创建一个实例才能使用它,如下所示:
@Rule
public ErrorCollector collector= new ErrorCollector();
这似乎是Runner中的一个bug:
//Correct variants:
@Rule
public ErrorCollector collector1= new ErrorCollector();
public ErrorCollector collector2= null;
@Rule
collector2= new ErrorCollector();
public ErrorCollector collector3;
@Rule
collector3= new ErrorCollector();
// incorrect variants:
@Rule
public ErrorCollector collector4= null;
@Rule
public ErrorCollector collector5;
@Rule
public ErrorCollector collector5=somethingThatIsNotRule;
@Rule
public ErrorCollector collector5=anotherRule;
//BUT:
//the runner takes the following, and runs it without problems, too:
public ErrorCollector collector6= null;
{
@Rule
collector6= null;
}
因此,运行程序在构建测试之前进行了过度检查。这似乎是运行程序中的一个错误:
//Correct variants:
@Rule
public ErrorCollector collector1= new ErrorCollector();
public ErrorCollector collector2= null;
@Rule
collector2= new ErrorCollector();
public ErrorCollector collector3;
@Rule
collector3= new ErrorCollector();
// incorrect variants:
@Rule
public ErrorCollector collector4= null;
@Rule
public ErrorCollector collector5;
@Rule
public ErrorCollector collector5=somethingThatIsNotRule;
@Rule
public ErrorCollector collector5=anotherRule;
//BUT:
//the runner takes the following, and runs it without problems, too:
public ErrorCollector collector6= null;
{
@Rule
collector6= null;
}
因此,运行程序在构建测试之前进行了过度检查。您是否应该创建
ErrorCollector
的实例?比如:publicstaticerrorcollector=newerrorcollector()代码>。请看@JoseRenato,它甚至在javadoc中。添加一个答案,我来投票。@MatthewFarwell它就在那里。你不应该创建一个ErrorCollector
的实例吗?比如:publicstaticerrorcollector=newerrorcollector()代码>。请看@JoseRenato,它甚至在javadoc中。加上一个答案,我就投赞成票。@MatthewFarwell它就在那里,很有效。但我不明白,为什么。javadocs中显示的可能性并不意味着我们必须使用它,是吗?我再问一个问题。非常感谢大家现在代码是什么?是否删除了静态
修改器?或者只是创建了ErrorCollector
的实例?它可以工作。但我不明白,为什么。javadocs中显示的可能性并不意味着我们必须使用它,是吗?我再问一个问题。非常感谢大家现在代码是什么?是否删除了静态
修改器?还是刚刚创建了ErrorCollector
的实例?