在安装CentOS6.4时，系统会自动安装jdk，先把它下载掉，装上自定义的jdk。
卸载步骤如下：
[root@localhost ~]# rpm -qa|grep jdk java-1.6.0-openjdk-1.6.0.0-1.50.1.11.5.el6_3.x86_64 java-1.7.0-openjdk-1.7.0.9-2.3.4.1.el6_3.x86_64 [root@localhost ~]# rpm -qa|grep gcj java-1.4.2-gcj-compat-1.4.2.0-40jpp.115 libgcj-4.1.2-48.el5 [root@localhost ~]# yum -y remove java java-1.6.0-openjdk-1.6.0.0-1.50.1.11.5.el6_3.x86_64 [root@localhost ~]# yum -y remove java java-1.7.0-openjdk-1.7.0.9-2.3.4.1.el6_3.x86_64 [root@localhost ~]# yum -y remove java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115 [root@localhost ~]# yum -y remove libgcj-4.1.2-48.el5
先查看有哪些可安装的 yum list java* 选择要安装的包 yum install -y java-1.8.0-openjdk-devel.x86_64 等待安装完成执行java -version vim /etc/profile MAVEN_HOME=/usr/local/maven3 export MAVEN_HOME export PATH=${PATH}:${MAVEN_HOME}/bin export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/jre/lib/rt.jar export PATH=$PATH:$JAVA_HOME/bin