查看CentOS自带JDK是否已安装
[root@test ~]# yum list installed |grep java
若有自带安装的JDK，应如下操作进行卸载CentOS系统自带Java环境
[root@test ~]# java -version java version "1.7.0_181" OpenJDK Runtime Environment (rhel-2.6.14.8.el6_9-x86_64 u181-b00) OpenJDK 64-Bit Server VM (build 24.181-b00, mixed mode) [root@test ~]# yum -y remove java-1.7.0-openjdk* [root@test ~]# yum -y remove tzdata-java.noarch [root@test ~]# java --version -bash: /usr/bin/java: No such file or directory
查看yum库中的Java安装包
[root@test ~]# yum -y list java* Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: centos.ustc.edu.cn * extras: centos.ustc.edu.cn * updates: centos.ustc.edu.cn base | 3.7 kB 00:00 extras | 3.4 kB 00:00 updates | 3.4 kB 00:00 Available Packages java-1.5.0-gcj.x86_64 1.5.0.0-29.1.el6 base java-1.5.0-gcj-devel.x86_64 1.5.0.0-29.1.el6 base java-1.5.0-gcj-javadoc.x86_64 1.5.0.0-29.1.el6 base java-1.5.0-gcj-src.x86_64 1.5.0.0-29.1.el6 base java-1.6.0-openjdk.x86_64 1:1.6.0.40-1.13.12.6.el6_8 updates java-1.6.0-openjdk-demo.x86_64 1:1.6.0.40-1.13.12.6.el6_8 updates java-1.6.0-openjdk-devel.x86_64 1:1.6.0.40-1.13.12.6.el6_8 updates java-1.6.0-openjdk-javadoc.x86_64 1:1.6.0.40-1.13.12.6.el6_8 updates java-1.6.0-openjdk-src.x86_64 1:1.6.0.40-1.13.12.6.el6_8 updates java-1.7.0-openjdk.x86_64 1:1.7.0.111-2.6.7.2.el6_8 updates java-1.7.0-openjdk-demo.x86_64 1:1.7.0.111-2.6.7.2.el6_8 updates java-1.7.0-openjdk-devel.x86_64 1:1.7.0.111-2.6.7.2.el6_8 updates java-1.7.0-openjdk-javadoc.noarch 1:1.7.0.111-2.6.7.2.el6_8 updates java-1.7.0-openjdk-src.x86_64 1:1.7.0.111-2.6.7.2.el6_8 updates java-1.8.0-openjdk.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-debug.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-demo.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-demo-debug.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-devel.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-devel-debug.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-headless.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-headless-debug.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-javadoc.noarch 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-javadoc-debug.noarch 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-src.x86_64 1:1.8.0.101-3.b13.el6_8 updates java-1.8.0-openjdk-src-debug.x86_64 1:1.8.0.101-3.b13.el6_8 updates java_cup.x86_64 1:0.10k-5.el6 base java_cup-javadoc.x86_64 1:0.10k-5.el6 base java_cup-manual.x86_64 1:0.10k-5.el6 base javacc.x86_64 4.1-0.5.el6 base javacc-demo.x86_64 4.1-0.5.el6 base javacc-manual.x86_64 4.1-0.5.el6 base javassist.noarch 3.9.0-6.el6 base javassist-javadoc.noarch 3.9.0-6.el6 base
以yum库中java-1.8.0为例, "*"表示将java-1.8.0的所有相关Java程序都安装上
[root@test ~]# yum -y install java-1.8.0-openjdk*
查看刚安装的Java版本信息。
输入："java -version" 可查看Java版本
输入："javac" 可查看Java的编译器命令用法