CentOS7 use the Yum command to install Java Jdk1.8__java

view Self-brought Java information

[Root@zck ~]# Java-version
Java Version "1.7.0_"
OpenJDK Runtime Environment (IcedTea6 1.11.1) (rhel-1.45.1.11.1.el6-x86_64)
OpenJDK 64-bit Server VM (build 20.0-b12, Mixed mode) to further view JDK information:

[Root@localhost ~]# Rpm-qa | grep java
Javapackages-tools-3.4.1-6.el7_0.noarch
Tzdata-java-2014i-1.el7.noarch
Java-1.7.0-openjdk-headless-1.7.0.71-2.5.3.1.el7_0.x86_64
Java-1.7.0-openjdk-1.7.0.71-2.5.3.1.el7_0.x86_64
Python-javapackages-3.4.1-6.el7_0.noarch Uninstall OpenJDK, do the following:

[Root@localhost ~]# rpm-e–nodeps Tzdata-java-2014i-1.el7.noarch
[Root@localhost ~]# rpm-e–nodeps java-1.7.0-openjdk-headless-1.7.0.71-2.5.3.1.el7_0.x86_64
[Root@localhost ~]# rpm-e–nodeps java-1.7.0-openjdk-1.7.0.71-2.5.3.1.el7_0.x86_64

Rpm-e–nodeps Tzdata-java-2017b-1.el7.noarch
Rpm-e–nodeps java-1.7.0-openjdk-1.7.0.141-2.6.10.1.el7_3.x86_64
Rpm-e–nodeps java-1.7.0-openjdk-headless-1.7.0.141-2.6.10.1.el7_3.x86_64

Rpm-e–nodeps Tzdata-java-2017b-1.el7.noarch
Rpm-e–nodeps java-1.8.0-openjdk-headless-1.8.0.141-1.b16.el7_3.x86_64
Rpm-e–nodeps java-1.8.0-openjdk-1.8.0.141-1.b16.el7_3.x86_64 installation mode: 1, enter the following command to view the list of available JDK packages;

Yum Search Java | Grep-i–color JDK 2, installing the JAVA SDK on CentOS Linux

At the command line terminal, enter the following command with root user yum install Opensdk:

Yum Install java-1.8.0-openjdk java-1.8.0-openjdk-devel #安装openjdk

The completion of the above command indicates that the JDK installation was successful. 3. Set up java_home environment variable on CentOS Linux (java_home environment variable)

After Rhel and CentOS Linux use the yum command, install OPENSDK to the/usr/lib/jvm/directory:

4, with the CD command into the JVM under the only directory java-1.8.0-openjdk-1.8.0.51.x86_64, and jre-1.8.0-openjdk.x86_64 this link is to point to Java-1.8.0-openjdk-1.8.0.51.x86_64 This folder, so you can directly use the Export command to point java_home to jre-1.8.0-openjdk.x86_64 this link.
Even with the Export command:

Export java_home=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.51.x86_64

However, this can only be effective in the current session, once the log off, the failure. 5, the standard way to configure environment variables

Do the following:

Vi/etc/profile

Paste the following three lines into the/etc/profile:
Export java_home=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.51.x86_64
Export classpath=.: javahome/jre/lib/rt.jar:java_home/jre/lib/rt.jar:java_home/lib/dt.jar:javahome/lib/ Tools.jarexportpath= Java_home/lib/tools.jar export Path=path: $JAVA _home/bin

Save shutdown, after execution: Source/etc/profile #让设置立即生效.

Verify that the three variables are set to what we want by entering the following command:

[root@~]# Echo Java_home
[root@ ~]# echojava_home [root@ ~]# Echo CLASSPATH
[Root@ ~]# Echo $PATH

echo $JAVA _home
echo $CLASSPATH echo
$PATH

Export java_home=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.141-1.b16.el7_3.x86_64
export classpath=.: $JAVA _home/ Jre/lib/rt.jar: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar
export path= $PATH: $JAVA _home/bin

# Reboot reboot machine configuration takes effect
or execute the following command to take effect immediately

Source/etc/profile

There are two JDK when configuring Java_home it was very depressing to pick a random one, question a
Source/etc/profile run times wrong question two but no effect javac that's weird

Etc/profile:fork:cannot Allocate Memory
etc/profile:line 80:export: ' java-1.8.0-openjdk ': not a valid identifier

6, test whether the installation of Java configuration Success

To view the Java version, enter the command:
[root@~]# java-version

7, the creation of a Java applet test, named Helloworld.java, enter the following command:
[root@ ~]# Touch Helloworld.java

Copy the following code into Helloworld.java:

public class HelloWorld {public
        static void Main (string[] args) {
            System.out.println ("Hello, world! This is a test code by nixcraft! ");
        }
    

After you copy it in, save the closing file. Compile and run this applet and enter the following command:
[root@ ~]# Javac Helloworld.java
[root@ ~]# Java HelloWorld

Will get the following display:
Hello, world!. This is a test code by nixcraft!
8. How (how) to run. Java applications such as jars.

The syntax is as follows:
[root@~]# Java-jar File.jar
[root@~]# Java-jar/path/to/my/java/app.jar #/path/to/my/java/app.jar represents the path of the application
[root@ ~]# Java-jar/path/to/my/java/app.jar arg1 arg2 # arg1 represents parameter 1, arg2 represents parameter 2