注意:这个问题是在Oracle将OpenJDK作为Oracle JDK的免费版本之前提出的，历史上的答案反映了这一点。从2022年开始，你不应该使用Java 7，除非你必须在不能在OpenJDK 8上运行的项目中使用。
要从终端安装java，我一直使用经典的方式。 我想手动安装java。 我把JDK的文件夹放在桌上，设置环境变量(PATH, CLASSPATH和JAVA_HOME)。 在终端上，如果我输入java -version，就会打印出来
foralobo@ubuntu-vincy:~$ java -version
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)
但是当我尝试安装eclipse或netbeans时，系统警告说机器上没有安装java。
完成手动安装需要什么? (Ubuntu 13.04)
当前回答
Open Applicaction -> Accessories -> Terminal
Type commandline as below...
sudo apt-get install openjdk-7-jdk
Type commandline as below...
apt-cache search jdk
(Note: openjdk-7-jdk is symbolically used here. You can choose the JDK version as per your requirement.)
For "JAVA_HOME" (Environment Variable) type command as shown below, in "Terminal" using your installation path...
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk
(Note: "/usr/lib/jvm/java-7-openjdk" is symbolically used here just for demostration. You should use your path as per your installation.)
For "PATH" (Environment Variable) type command as shown below, in "Terminal" using your installation path...
export PATH=$PATH:/usr/lib/jvm/java-7-openjdk/bin
(Note: "/usr/lib/jvm/java-7-openjdk" is symbolically used here just for demostration. You should use your path as per your installation.)
Check for "open jdk" installation, just type command in "Terminal" as shown below
javac -version
其他回答
Oracle和现代版本的Ubuntu已经迁移到更新版本的Java。Ubuntu 20.04的默认版本是OpenJDK 11，这对于大多数用途来说已经足够好了。
如果你真的需要它来运行遗留程序，OpenJDK 8也可以从官方存储库中获得。
如果你真的需要Java 7，到2020年最好的选择是下载一个Zulu发行版。如果您拥有root权限，最简单的安装方法是. deb版本，否则请下载. zip版本。
https://www.azul.com/downloads/?version=java-7-lts&os=ubuntu&architecture=x86-64-bit&package=jdk#download-openjdk
注:根据评论，这篇文章是从GIST复制而来的，没有注明出处。
从https://www.oracle.com/technetwork/java/javase/downloads/index.html下载java jdk<version>-linux-x64.tar.gz文件。
将该文件解压缩到您想要的位置。例如:/home/java(用户在主目录下创建的文件夹名称)。
现在打开终端。 设置路径JAVA_HOME= jdk文件夹的路径(打开jdk文件夹，然后右键单击任何文件夹，进入属性，然后使用select all复制路径) 粘贴在这里。
如:JAVA_HOME = / home / xxxx / java / JDK1.8.0_201
让Ubuntu知道我们的JDK/JRE的位置。
sudo update-alternatives --install /usr/bin/java java /home/xxxx/java/jdk1.8.0_201/bin/java 20000
sudo update-alternatives --install /usr/bin/javac javac /home/xxxx/java/jdk1.8.0_201/bin/javac 20000
sudo update-alternatives --install /usr/bin/javaws javaws /home/xxxx/java/jdk1.8.0_201/bin/javaws 20000
告诉Ubuntu我们的安装，例如jdk1.8.0_05必须是默认的Java。
sudo update-alternatives --set java /home/xxxx/sipTest/jdk1.8.0_201/bin/java
sudo update-alternatives --set javac /home/xxxx/java/sipTest/jdk1.8.0_201/bin/javac
sudo update-alternatives --set javaws /home/xxxxx/sipTest/jdk1.8.0_201/bin/javaws
现在试一试:
$ sudo update-alternatives --config java
有3种可供选择的java(提供/usr/bin/java)。
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-6-oracle1/bin/java 1047 auto mode
1 /usr/bin/gij-4.6 1046 manual mode
2 /usr/lib/jvm/java-6-oracle1/bin/java 1047 manual mode
3 /usr/lib/jvm/jdk1.7.0_75/bin/java 1 manual mode
按enter键保持当前选择[*]，或键入选择数字:3
update-alternatives: using /usr/lib/jvm/jdk1.7.0_75/bin/java to provide /usr/bin/java (java) in manual mode
重复以上步骤:
sudo update-alternatives --config javac
sudo update-alternatives --config javaws
Open Applicaction -> Accessories -> Terminal
Type commandline as below...
sudo apt-get install openjdk-7-jdk
Type commandline as below...
apt-cache search jdk
(Note: openjdk-7-jdk is symbolically used here. You can choose the JDK version as per your requirement.)
For "JAVA_HOME" (Environment Variable) type command as shown below, in "Terminal" using your installation path...
export JAVA_HOME=/usr/lib/jvm/java-7-openjdk
(Note: "/usr/lib/jvm/java-7-openjdk" is symbolically used here just for demostration. You should use your path as per your installation.)
For "PATH" (Environment Variable) type command as shown below, in "Terminal" using your installation path...
export PATH=$PATH:/usr/lib/jvm/java-7-openjdk/bin
(Note: "/usr/lib/jvm/java-7-openjdk" is symbolically used here just for demostration. You should use your path as per your installation.)
Check for "open jdk" installation, just type command in "Terminal" as shown below
javac -version
Oracle Java 1.7.0的。deb包
wget https://raw.github.com/flexiondotorg/oab-java6/master/oab-java.sh
chmod +x oab-java.sh
sudo ./oab-java.sh -7
sudo apt-get update
sudo sudo apt-get install oracle-java7-jdk oracle-java7-fonts oracle-java7-source
sudo apt-get dist-upgrade
1.7.0_51的解决方案
有一个问题123目前在OAB和一个拉请求
以下是补丁版本:
wget https://raw.github.com/ladios/oab-java6/master/oab-java.sh
chmod +x oab-java.sh
sudo ./oab-java.sh -7
sudo apt-get update
sudo sudo apt-get install oracle-java7-jdk oracle-java7-fonts oracle-java7-source
sudo apt-get dist-upgrade
sudo apt-get update
sudo apt-get install openjdk-7-jdk
以及是否已经安装了其他JDK版本
sudo update-alternatives --config java
然后选择java7版本。
