Java configuration in Linux

Today, JDK is installed in Linux, and there is a small problem in the environment variable classpath settings. after a long time of searching the Internet, I found that there are very few mentioned, maybe it is too simple for everyone, there is no need to write it. Let's write it down by yourself. If a brother makes the same mistake in the future, something can be found.

1. Install JDK

Download JDK directly from Sun: The http://java.sun.com/j2se/1.4.2/download.html provides two downloads:

1,Rpm in self-extracting File(J2sdk-1_4_2_04-linux-i586.bin, 32.77 MB) This is a self-extracting file, installed on Linux as follows:

# Chmod U + X./j2sdk-1_4_2_04-linux-i586.bin

#./J2sdk-1_4_2_04-linux-i586.bin

After entering YES as prompted, JDK is decompressed to The./j2sdk1.4.2 _ 04 directory. In order to be consistent with the JDK installation path in the following 2, we will perform the following operations to establish the installation path under/usr/Java and test the file to this path:

# Mkdir/usr/Java

# Cp-Fr./j2sdk1.4.2 _ 04/usr/Java

 

2,Rpm in self-extracting File(J2sdk-1_4_2_04-linux-i586-rpm.bin, 32.77 MB) This is also a self-extracting file, but the decompressed file is a j2sdk-1_4_2_04-linux-i586-rpm package, run the RPM command to install it on Linux. The installation is as follows:

# Chmod U + X./j2sdk-1_4_2_04-linux-i586-rpm.bin

#./J2sdk-1_4_2_04-linux-i586-rpm.bin

# Rpm-IVH j2sdk-1_4_2_04-linux-i586-rpm

The installation software automatically installs JDK in the/usr/Java/j2sdk1.4.2 _ 04 directory.

2. Configure Environment Variables

1. Modify user environment variables

Assume that the Java User is kunp. Edit the user's. bashrc file to set environment variables.

# Vi/home/kunp/. bashrc

Add the following to the. bashrc file:

Export java_home =/usr/Java/j2sdk1.4.2 _ 04
Export classpath = $ classpath: $ java_home/lib: $ java_home/JRE/lib
Export Path = $ java_home/bin: $ java_home/JRE/bin: $ path: $ homr/bin

2. Modify the environment variables of all users

# Vi/etc/profile

Add:

Export java_home =/usr/Java/j2sdk1.4.2 _ 04
Export classpath = $ classpath: $ java_home/lib: $ java_home/JRE/lib
Export Path = $ java_home/bin: $ java_home/JRE/bin: $ path: $ homr/bin

Be sure to add $ classpath to the classpath path: Because I didn't add this stuff before, I always reported an error when interpreting and executing the class file.

Now let's see if Java is fully installed. Compile the most powerful Java file:

Hellodate. Java

-----------------------------------------

// Hellodate. Java
Import java. util. date;

Public class hellodate {
Public static void main (string [] ARGs ){
System. Out. println ("Hello, it's :");
System. Out. println (new date ());
}
}

------------------------------------------

Compile and execute the file under the kunp User:

# Su-kunp

$ Javac hellodate. Java
$ Java hellodate
Hello, it's:
Thu Jun 10 14:21:21 CST 2004

 

OK. The Java environment has been set up. Start to write your Java program.