成都房地产网站开发,如何做阿里巴巴的网站首页,如何做网站出单,公司网站建设调研【README】
本文主要介绍java运行环境变量的获取#xff0c;如何读取 env.properties 文件并将自定义变量写入到系统变量#xff1b; 【1】System.getenv() 获取环境变量
public static void main1() {MapString, String envMap System.getenv();envMap.entrySet(…【README】
本文主要介绍java运行环境变量的获取如何读取 env.properties 文件并将自定义变量写入到系统变量 【1】System.getenv() 获取环境变量
public static void main1() {MapString, String envMap System.getenv();envMap.entrySet().forEach(x- System.out.println(x.getKey() x.getValue()));}
System.getenv() 获取的是操作系统环境变量列表如下 【2】 System.getProperties()获取java运行时环境变量 public static void main2() {Properties props System.getProperties();props.list(System.out);}
-- listing properties --
java.runtime.nameJava(TM) SE Runtime Environment
sun.boot.library.pathD:\Java\jdk1.8.0_172\jre\bin
java.vm.version25.172-b11
java.vm.vendorOracle Corporation
java.vendor.urlhttp://java.oracle.com/
path.separator;
java.vm.nameJava HotSpot(TM) 64-Bit Server VM
file.encoding.pkgsun.io
user.script
user.countryCN
sun.java.launcherSUN_STANDARD
sun.os.patch.level
java.vm.specification.nameJava Virtual Machine Specification
user.dirD:\bench-cluster\spring_in_action_ecl...
java.runtime.version1.8.0_172-b11
java.awt.graphicsenvsun.awt.Win32GraphicsEnvironment
java.endorsed.dirsD:\Java\jdk1.8.0_172\jre\lib\endorsed
os.archamd64
java.io.tmpdirC:\Users\zhangsan\AppData\Local\Temp\
line.separatorjava.vm.specification.vendorOracle Corporation
user.variant
os.nameWindows 10
sun.jnu.encodingGBK
java.library.pathD:\Java\jdk1.8.0_172\bin;C:\WINDOWS\S...
java.specification.nameJava Platform API Specification
java.class.version52.0
sun.management.compilerHotSpot 64-Bit Tiered Compilers
os.version10.0
user.homeC:\Users\zhangsan
user.timezone
java.awt.printerjobsun.awt.windows.WPrinterJob
file.encodingUTF-8
java.specification.version1.8
user.namezhangsan
java.class.pathD:\Java\jdk1.8.0_172\jre\lib\charsets...
java.vm.specification.version1.8
sun.arch.data.model64
java.homeD:\Java\jdk1.8.0_172\jre
sun.java.commandcom.swjtu.mybatis.main.Main2
java.specification.vendorOracle Corporation
user.languagezh
awt.toolkitsun.awt.windows.WToolkit
java.vm.infomixed mode
java.version1.8.0_172
java.ext.dirsD:\Java\jdk1.8.0_172\jre\lib\ext;C:\W...
sun.boot.class.pathD:\Java\jdk1.8.0_172\jre\lib\resource...
java.vendorOracle Corporation
file.separator\
java.vendor.url.bughttp://bugreport.sun.com/bugreport/
sun.cpu.endianlittle
sun.io.unicode.encodingUnicodeLittle
sun.desktopwindows
sun.cpu.isalistamd64zheshi 【3】自定义变量
1新建 env.properties 文件 填写变量 2读取 自定义变量文件env.properties 文件
// 自定义变量public static void main3() {Properties envProps new Properties();try {// 使用 mybatis Resources工具读取环境属性文件envProps.load(Resources.getResourceAsStream(env.properties));} catch (IOException e) {}// 把自定义变量填充到系统变量 SystemPropertiesenvProps.stringPropertyNames().forEach(x-{System.getProperties().setProperty(x, envProps.getProperty(x));});System.out.println(System.getenv());System.getProperties().list(System.out);} 【4】几个常用系统变量
Properties sysProps System.getProperties();
System.out.println(user.dir sysProps.getProperty(user.dir));
System.out.println(java.class.path sysProps.getProperty(java.class.path));
System.out.println(sun.java.command sysProps.getProperty(sun.java.command));
System.out.println(file.separator sysProps.getProperty(file.separator));
System.out.println(file.encoding sysProps.getProperty(file.encoding));
user.dirD:\bench-cluster\spring_in_action_eclipse\MybatisHello3_mapper
java.class.pathD:\Java\jdk1.8.0_172\jre\lib\charsets.jar;D:\Java\jdk1.8.0_172\jre\lib\deploy.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\access-bridge-64.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\cldrdata.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\dnsns.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\jaccess.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\jfxrt.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\localedata.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\nashorn.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunec.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunjce_provider.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunmscapi.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunpkcs11.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\zipfs.jar;D:\Java\jdk1.8.0_172\jre\lib\javaws.jar;D:\Java\jdk1.8.0_172\jre\lib\jce.jar;D:\Java\jdk1.8.0_172\jre\lib\jfr.jar;D:\Java\jdk1.8.0_172\jre\lib\jfxswt.jar;D:\Java\jdk1.8.0_172\jre\lib\jsse.jar;D:\Java\jdk1.8.0_172\jre\lib\management-agent.jar;D:\Java\jdk1.8.0_172\jre\lib\plugin.jar;D:\Java\jdk1.8.0_172\jre\lib\resources.jar;D:\Java\jdk1.8.0_172\jre\lib\rt.jar;D:\bench-cluster\spring_in_action_eclipse\MybatisHello3_mapper\target\classes;D:\software_cluster\mvn_repo\.m2\repository\org\mybatis\mybatis\3.4.1\mybatis-3.4.1.jar;D:\software_cluster\mvn_repo\.m2\repository\mysql\mysql-connector-java\8.0.11\mysql-connector-java-8.0.11.jar;D:\software_cluster\mvn_repo\.m2\repository\com\google\protobuf\protobuf-java\2.6.0\protobuf-java-2.6.0.jar;D:\software_cluster\mvn_repo\.m2\repository\org\apache\logging\log4j\log4j-core\2.11.0\log4j-core-2.11.0.jar;D:\software_cluster\mvn_repo\.m2\repository\org\apache\logging\log4j\log4j-api\2.11.0\log4j-api-2.11.0.jar;D:\Program Files\IntelliJ IDEA 2021.1\lib\idea_rt.jar
sun.java.commandcom.swjtu.mybatis.main.Main2
file.separator\
file.encodingUTF-8
1常用系统变量列表
user.dir 当前项目根目录java.class.path java运行时环境路径sum.java.command 主程序所在类的全限定类名file.separator 文件路径分隔符file.encoding文件编码
其中 file.encoding 是通过jvm运行时参数指定的 vm 参数如下
D:\Java\jdk1.8.0_172\bin\java.exe -javaagent:D:\Program Files\IntelliJ IDEA 2021.1\lib\idea_rt.jar49223:D:\Program Files\IntelliJ IDEA 2021.1\bin -Dfile.encodingUTF-8 -classpath D:\Java\jdk1.8.0_172\jre\lib\charsets.jar;D:\Java\jdk1.8.0_172\jre\lib\deploy.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\access-bridge-64.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\cldrdata.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\dnsns.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\jaccess.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\jfxrt.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\localedata.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\nashorn.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunec.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunjce_provider.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunmscapi.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\sunpkcs11.jar;D:\Java\jdk1.8.0_172\jre\lib\ext\zipfs.jar;D:\Java\jdk1.8.0_172\jre\lib\javaws.jar;D:\Java\jdk1.8.0_172\jre\lib\jce.jar;D:\Java\jdk1.8.0_172\jre\lib\jfr.jar;D:\Java\jdk1.8.0_172\jre\lib\jfxswt.jar;D:\Java\jdk1.8.0_172\jre\lib\jsse.jar;D:\Java\jdk1.8.0_172\jre\lib\management-agent.jar;D:\Java\jdk1.8.0_172\jre\lib\plugin.jar;D:\Java\jdk1.8.0_172\jre\lib\resources.jar;D:\Java\jdk1.8.0_172\jre\lib\rt.jar;D:\bench-cluster\spring_in_action_eclipse\MybatisHello3_mapper\target\classes;D:\software_cluster\mvn_repo\.m2\repository\org\mybatis\mybatis\3.4.1\mybatis-3.4.1.jar;D:\software_cluster\mvn_repo\.m2\repository\mysql\mysql-connector-java\8.0.11\mysql-connector-java-8.0.11.jar;D:\software_cluster\mvn_repo\.m2\repository\com\google\protobuf\protobuf-java\2.6.0\protobuf-java-2.6.0.jar;D:\software_cluster\mvn_repo\.m2\repository\org\apache\logging\log4j\log4j-core\2.11.0\log4j-core-2.11.0.jar;D:\software_cluster\mvn_repo\.m2\repository\org\apache\logging\log4j\log4j-api\2.11.0\log4j-api-2.11.0.jar com.swjtu.mybatis.main.Main2
即通过 -Dfile.encodingUTF-8 指定的jvm参数可以通过 System.getProperties() 获取到
