设置JAVA_HOME& CLOSSPATH在CentOS 6 [英] setting JAVA_HOME & CLASSPATH in CentOS 6

问题描述

我已经解压缩我的jdk在/ usr / java /.

I have unpacked my jdk in /usr/java/.

，我把CLASSPATH，PATH，JAVA_HOME放入/ etc /

and I put CLASSPATH, PATH, JAVA_HOME into /etc/profile like below.

export JAVA_HOME=/usr/java/jdk1.7.0_21
export PATH=$PATH:$JAVA_HOME/bin
export CLASSPATH=$JAVA_HOME/jre/lib/ext:$JAVA_HOME/lib/tools.jar

当我在/usr/java/jdk1.0.7_21/bin中编译一些java文件时，

And when I compile some java file in /usr/java/jdk1.0.7_21/bin,

它工作。但是当我在其他文件夹上做同样的事情时，它不会。

it works. But when I am doing same thing on other folder, it doesn't.

它显示NoClassDefFoundError。

It displays NoClassDefFoundError.

所以我通过echo检查了ClASSPATH，PATH，JAVA_HOME。

So I have checked ClASSPATH, PATH, JAVA_HOME via echo.

它显示如下。

[root@localhost a]# echo $JAVA_HOME
/usr/java/jdk1.7.0_21
[root@localhost a]# echo $PATH
/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/guest/bin:/usr/java/jdk1.7.0_21/bin:/usr/java/bin:/usr/java/jdk1.7.0_21/bin
[root@localhost a]# echo $CLASSPATH
/usr/java/jdk1.7.0_21/jre/lib/ext:/usr/java/jdk1.7.0_21/lib/tools.jar

我想在控制台中使用java，我该怎么办？

I want to use java in console, What can I do fir this situation?

提前感谢。

PS。的couse我做了 source / etc / profile 。

PS. of couse I did source /etc/profile.

============ =====错误，我面对的=======================

=================The Errors what I'm facing with =======================

当我命令java A（我的类名是A）。

when I command java A(My class name is A).

Error: Could not find or load main class A

case命令java -cp / home / guest / workspace / AAA / src / a / A

case I command java -cp /home/guest/workspace/AAA/src/a/ A

Exception in thread "main" java.lang.NoClassDefFoundError: A (wrong name: a/A)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:791)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

=====================我的代码的全部内容======= java部分。路径为/usr/guest/workspace/AAA/src/a/A.java

=====================full content of my code====================================== java part. path is /usr/guest/workspace/AAA/src/a/A.java

package a;

public class A {
    public static void main(String[] args) {
        System.out.println("a!\n");
    }
}

/ etc /左侧部分是默认值。

/etc/profile part. left part is default.

export JAVA_HOME=/usr/java/jdk1.7.0_21
export PATH=$PATH:$JAVA_HOME/bin
export CLASSPATH=$JAVA_HOME/jre/lib/ext:$JAVA_HOME/lib/tools.jar

其他部分可能有助于解决。

other parts might be helpful to solve.

• which java prints/ usr / java / bin。有符号链接。


• 我的jdk位置是/usr/java/jdk1.7.0_21。 ./bin每个代码都很好。


• 我没有碰/root/.bash_profile。我刚刚编辑了/ etc / profile。

• which java prints "/usr/java/bin". there's symbolic link.
• My jdk location is /usr/java/jdk1.7.0_21. inside of ./bin every code works fine.
• I did not touch /root/.bash_profile. I just edited /etc/profile.

感谢您的关注。即使它没有想出来。

Thanks for such interest. even though it does not figured out. your help was great healing to me :D Thanks again.

推荐答案

我在/ home / prasanth中创建了一个名为a的文件夹，然后复制你的代码到一个名为A.java的文件。我从/ home / prasanth中编译为 javac a / A.java 并运行 javac a.A 。我输出为

I created a folder named a in /home/prasanth and copied your code to a file named A.java. I compiled from /home/prasanth as javac a/A.java and run javac a.A. I got output as

a!

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