1. 檢查已經安裝的jdk
rpm -qa | grep java
可能的結果如下:
java-1.7.0-openjdk-1.7.0.99-2.6.5.0.el7_2.x86_64 python-javapackages-3.4.1-11.el7.noarch java-1.8.0-openjdk-headless-1.8.0.77-0.b03.el7_2.x86_64 java-1.8.0-openjdk-1.8.0.77-0.b03.el7_2.x86_64 tzdata-java-2016c-1.el7.noarch javapackages-tools-3.4.1-11.el7.noarch java-1.7.0-openjdk-headless-1.7.0.99-2.6.5.0.el7_2.x86_64
2. 移除已經安裝的open-jdk及依賴的程序
yum remove tzdata-java-2016c-1.el7.noarch
此時所有的open-jdk和其它對open-jdk有依賴的軟件都會被移除
3.到oracle下載jdk8, 如我下載的是jdk-8u65-linux-x64.rpm
在對應目錄下執行安裝命令:
rpm -ivh jdk-8u65-linux-x64.rpm
程序默認安裝到 /usr/java/jdk1.8.0_65
檢查安裝情況:
[root@pole jdk]# java -version java version "1.8.0_65" Java(TM) SE Runtime Environment (build 1.8.0_65-b17) Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode) [root@pole jdk]# javac -version javac 1.8.0_65
檢查文件路徑:
[root@pole jdk]# whereis java java: /usr/bin/java /usr/lib/java /etc/java /usr/share/java /usr/share/man/man1/java.1 [root@pole jdk]# ll /usr/bin/java lrwxrwxrwx 1 root root 22 Mar 28 11:52 /usr/bin/java -> /etc/alternatives/java [root@pole jdk]# ll /etc/alternatives/java lrwxrwxrwx 1 root root 34 Mar 28 11:52 /etc/alternatives/java -> /usr/java/jdk1.8.0_65/jre/bin/java
添加環境變量文件:
[root@pole jdk]# vi /etc/profile.d/jdk8.sh
添加以下內容
JAVA_HOME=/usr/java/jdk1.8.0_65 JRE_HOME=/usr/java/jdk1.8.0_65/jre CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib export JAVA_HOME JRE_HOME CLASSPATH
使修改生效
source /etc/profile
檢查是否生效
[root@pole jdk]# env|grep java JRE_HOME=/usr/java/jdk1.8.0_65/jre JAVA_HOME=/usr/java/jdk1.8.0_65 CLASSPATH=.:/usr/java/jdk1.8.0_65/lib/dt.jar:/usr/java/jdk1.8.0_65/lib/tools.jar:/usr/java/jdk1.8.0_65/jre/lib
到此OK了.