当我通过WebDriver浏览我们正在测试的视频播放器应用程序时,我正在运行Browsermob代理,因此我可以阅读我们的Web服务调用的标题和内容。具体来说,我想确保在驱动程序点击给定链接时传递正确的视频文件名。
我想将BrowserMob生成的HAR对象转换为字符串,以便我可以在字符串中搜索video_filename.flv
或其他内容。代理服务器具有writeTo()
功能,可将其内容转储为file
,OutputStream
或Writer
。现在,愚蠢的是,我将结果转储到一个文件,然后将文件直接摄入一个字符串并解析它:
//...lots of WebDriver activity up here with BMP listening
//...
//get the HAR data
Har har = server.getHar();
//Output HAR to a file
FileOutputStream fos = null;
try {
fos = new FileOutputStream("C:\\output.txt");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
try {
har.writeTo(fos);
} catch (IOException e) {
e.printStackTrace();
}
String harString = readFile("C:\\output.txt", StandardCharsets.UTF_8);
System.out.println(harString);
这很有效。
当我用Writer
或OutputStream
尝试同样的事情时,在我甚至担心将这些类型之一转换为字符串之前,我会抱怨这些是空指针。考虑一下:
//get the HAR data
Har har = server.getHar();
//Output HAR to a Writer
Writer harWriter = null;
try {
har.writeTo(harWriter);
} catch (IOException e) {
e.printStackTrace();
}
返回空指针异常。
同样适用于OutputStream
。在尝试harWriter
之前,应该将writeTo()
设置为某个非空值吗?我该如何做到这一点?
看,堆栈跟踪:
java.lang.NullPointerException
at org.codehaus.jackson.impl.WriterBasedGenerator._flushBuffer(WriterBasedGenerator.java:1187)
at org.codehaus.jackson.impl.WriterBasedGenerator.close(WriterBasedGenerator.java:837)
at org.codehaus.jackson.map.ObjectMapper._configAndWriteValue(ObjectMapper.java:2004)
at org.codehaus.jackson.map.ObjectMapper.writeValue(ObjectMapper.java:1581)
at net.lightbody.bmp.core.har.Har.writeTo(Har.java:30)
at com.videoplayer.CorrectVideosAreSentToThePlayer.teardown(CorrectVideosAreSentToThePlayer.java:152)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:33)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:77)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:195)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:63)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
答案 0 :(得分:0)
是的,当然如果你尝试写入null,你会得到一个NullPointerException!为什么你认为这会起作用?
你需要写一个StringWriter
或类似的东西。那会给你一个字符串。