[英]Runtime.exec doesn't compile java file
I compile java file by Runtime.exec("javac MyFrog.java"); 我通过Runtime.exec编译java文件(“javac MyFrog.java”); It says no errors, doesn't output anything, but doesn't create MyFrog.class file.
它表示没有错误,不输出任何内容,但不会创建MyFrog.class文件。 if i write Runtime.exec("javac") it outputs to output some help text.
如果我写Runtime.exec(“javac”),它输出输出一些帮助文本。 So I understand that program is working, but don't create class file.
所以我理解该程序正在运行,但不创建类文件。 Permissions are ok.
权限还可以。
javac -verbose
should give you lot more information, specifically the directory where the file is created. javac -verbose
应该为您提供更多信息,特别是创建文件的目录。 Since you are able to recognize output help text without any parameters, I assume you are capturing the process's stderr and assume you are doing the same for stdout as well (though javac does not seem to write anything to stdout). 由于您能够识别没有任何参数的输出帮助文本,我假设您正在捕获进程的stderr并假设您也对stdout执行相同的操作(尽管javac似乎没有向stdout写入任何内容)。
Where are you checking for the existence of the .class file? 你在哪里检查.class文件的存在? It is created in the same directory as the .java file.
它与.java文件在同一目录中创建。 If MyFrog.java has a package declaration it will not be created in the package sub-dir;
如果MyFrog.java有一个包声明,它将不会在包子目录中创建; for that you have to use
-d
argument. 因为你必须使用
-d
参数。
确保MyFrog.java
存在于工作目录中
尝试javac -verbose
并确保您的类路径设置正确。
You can use ProcessBuilder or Runtime.exec() method to create new process, 您可以使用ProcessBuilder或Runtime.exec()方法创建新进程,
String []cmd={"javac","Foo.java"};
Process proc=Runtime.getRuntime().exec(cmd);
proc.waitFor();
Or use ProcessBuilder 或者使用ProcessBuilder
ProcessBuilder pb = new ProcessBuilder("javac.exe","-verbose", "Foo.java");
pb.redirectErrorStream(true);
Process p = pb.start();
p.waitFor();
InputStream inp=p.getInputStream();
int no=inp.read();
while(no!=-1)
{
System.out.print((char)no);
no=inp.read();
}
我总是发现这个资源回答了有关Java exec的所有问题。
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