java 设置类路径。无法识别 javac
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setting up classpath. javac is not recognized
提问by kaboom
I am trying to run my java program from command line.
我正在尝试从命令行运行我的 java 程序。
I read an article about setting up classpath, but I get an error of javac is not recognized as internal or external command. What should I do? (I dont want to set a permanent CLASSPATH) This is what I have done in my command line
我读了一篇关于设置类路径的文章，但我收到了 javac 未被识别为内部或外部命令的错误。我该怎么办？（我不想设置永久的 CLASSPATH）这就是我在命令行中所做的
D:\user> set path=%path%;C:\Program Files\Java.7.0_07\bin
D:\user> cd testing
D:\user\testing> javac firstProgram.java
'javac' is not recognized as an internal or external command,
operable program or batch file.
Thank you
谢谢
回答by Stephen C
Assuming that the PATH is correct1, the most likely cause is that you have a JRE installation ... and a JRE doesn't include a java compiler. You need a JDK installation if you want to compile from the command line.
假设 PATH 是正确的1，最可能的原因是您安装了 JRE ......而 JRE 不包含 java 编译器。如果要从命令行编译，则需要安装 JDK。
(You can confirm this by looking in the C:\Program Files\Java\1.7.0_07\bindirectory to see if it contains a javac.exefile. A JRE won't ...)
（您可以通过查看C:\Program Files\Java\1.7.0_07\bin目录以查看它是否包含javac.exe文件来确认这一点。JRE 不会......）
Where can I find the Java compiler to download..
我在哪里可以找到要下载的 Java 编译器..
You need to download one of the JDK installers; see http://www.oracle.com/technetwork/java/javase/downloads/index.html
您需要下载 JDK 安装程序之一；见http://www.oracle.com/technetwork/java/javase/downloads/index.html
1 - I don't think quotes are required in a PATH variable on Windows. At least that's what various examples that Google found for me seem to imply. But I've never really understood the logic behind quoting in Windows ...
1 - 我认为 Windows 上的 PATH 变量中不需要引号。至少谷歌为我找到的各种例子似乎暗示了这一点。但我从来没有真正理解在 Windows 中引用背后的逻辑......
回答by madhairsilence
Better do it in Environmental variable and check it!
最好在环境变量中做并检查它！
回答by MouseCrasher
Its an issue related to Program Files.
它是一个与Program Files相关的问题。
First make sure that your JDK Folder is installed in Program Filesor Program Files(x86)or any other folder.
首先确保您的 JDK 文件夹安装在Program Files或Program Files(x86)或任何其他文件夹中。
Then you should use the path of bin folder in " ". Because command prompt does break the string at space. When you will write it in " " then it will take is as a whole String.
那么你应该使用“”中bin文件夹的路径。因为命令提示符确实会在空格处中断字符串。当你将它写在“”中时，它将作为一个完整的字符串。
You try these commands
你试试这些命令
set path=%path%;"C:\Program Files\Java.7.0_07\bin"
or
或者
set path=%path%;"C:\Program Files(x86)\Java.7.0_07\bin"
It might help you to get out of this.
它可能会帮助您摆脱困境。
回答by Satheesh Cheveri
try below command is recognized from command prompt C:\Program Files\Java\1.7.0_07\bin\javac ab.java
尝试从命令提示符 C:\Program Files\Java\1.7.0_07\bin\javac ab.java 识别以下命令
This is just to verify your javac
这只是为了验证您的 javac
回答by user2038944
Here's how you can set the path temporary, meaning if you close and reopen "command prompt" you will have to set the path again.
这是临时设置路径的方法，这意味着如果关闭并重新打开“命令提示符”，则必须再次设置路径。
Assuming the path is C:\Program Files\Java\jdk1.6.0\bin
假设路径是 C:\Program Files\Java\jdk1.6.0\bin
TYPE IN C:\Program Files\Java\jdk1.6.0\binAND HIT ENTER that's it.
输入 C:\Program Files\Java\jdk1.6.0\bin并按回车键。
回答by Duc Tran
The commands D:\user> set path=%path%;C:\Program Files\Java\1.7.0_07\binworks well for me
这些命令D:\user> set path=%path%;C:\Program Files\Java\1.7.0_07\bin对我来说效果很好
回答by adhoc
Adding few more information to this:
对此添加更多信息：
Please check the version of JDK and JRE installed on your computer. Recently I faced the same problem even after setting the PATH. It gives the error "javac - command is not recognised"
请检查您计算机上安装的 JDK 和 JRE 的版本。最近，即使设置了 PATH，我也遇到了同样的问题。它给出了错误“javac - 命令无法识别”
Solution is there must be similar versions of JDK as well as JRE
解决办法是必须有类似版本的JDK和JRE
E.g.: JDK 1.7.75 along with JRE 1.7.75
例如：JDK 1.7.75 和 JRE 1.7.75
