Install the jdk7 development environment in Linux and use linuxjdk7 for development.

Install the jdk7 development environment in Linux and use linuxjdk7 for development.
1Download JDK 7 from the official website

Address:

Http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase7-521261.html

Download Linux-jdk-7u80 version:

　　

Note: Use Login here (account: 96 **** 06@qq.com, password: X *** 1831234 *** 0)

2Use Xftp to upload files to the linux System for decompression

Put it in the/home/xiaohai/pack/directory.

Decompress the package:

   # tar -zxvf jdk-7u80-linux-x64.tar.gz

Move jdk to the/usr/local directory.

   # mv jdk1.7.0_80/ /usr/local/

3, Configure Environment Variables

 

Open the profile file

Run the following command:

   # vim /etc/profile

 

Add the following configuration at the end of the file:

　　export JAVA_HOME=/usr/local/jdk1.7.0_80　　export JRE_HOME=/usr/local/jdk1.7.0_80/jre 　　export PATH=$PATH:/usr/local/jdk1.7.0_80/bin 　　export CLASSPATH=./:/usr/local/jdk1.7.0_80/lib:/usr/local/jdk1.7.0_80/jre/lib

Or:

 

 

   JAVA_HOME=/usr/local/jdk1.7.0_80   JRE_HOME=/usr/local/jdk1.7.0_80/jre   CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib   PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin   export JAVA_HOME JRE_HOME CLASS_PATH PATH

Reload the file:

   # source /etc/profile

4Check whether the java version is successfully installed.

Run the following command:

Show version

    # java -version

Display execution Parameters

    # javac

5. Jdk version problems exist.

The default jdk environment of centOS7 is 1.8. When you view the version, the following figure is displayed:

　　

This is obviously not the information of the previous configuration. You need to modify some configurations:

View the java execution path

Run:

 # which java

　　

Enter the/usr/bin/path to display the soft connection of java:

　　

Go to the/etc/alternatives directory:

　　

The software points to the following path:

Java-& gt;/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.102-4.b14.el7.x86_64/jre/bin/java

Delete the soft link:

　　

  # rm java

Create a new java soft connection:

　　

 #ln -s /usr/local/jdk1.7.0_80/bin/java

Check again:

　　

In this way, you can point to the jdk path you configured and view the version: