java命令参数

java -help

Usage: java [-options] class [args...]

           (to execute a class)

   or  java [-options] -jar jarfile [args...]

           (to execute a jar file)

 

where options include:

    -client       to select the "client" VM

设置jvm使用client模式，特点是启动速度比较快，但运行时性能和内存管理效率不高，通常用于客户端应用程序或者PC应用开发和调试。

-server       to select the "server" VM

设置jvm使server模式，特点是启动速度比较慢，但运行时性能和内存管理效率很高，适用于生产环境。在具有64位能力的jdk环境下将默认启用该模式，而忽略-client参数。

    -hotspot      is a synonym for the "client" VM  [deprecated]

                  The default VM is client.

与-client相同。可以使用java –version检测使用是什么模式。

 

-cp <class search path of directories and zip/jar files>

类所在的文件夹或zip/jar

如例：D:\workspace\flash_builder_workspace\test_netty_server>java -cp bin com.log.test.Test3

com.log.test.Test3在bin文件夹下

    -classpath <class search path of directories and zip/jar files>

                  A ; separated list of directories, JAR archives,

                  and ZIP archives to search for class files.

    -D<name>=<value>

                  set a system property

 

设置系统属性名/值对，运行在此jvm之上的应用程序可用System.getProperty("property")得到value的值。

 如果value中有空格，则需要用双引号将该值括起来，如-Dname="space string"。

 该参数通常用于设置系统级全局变量值，如配置文件路径，以便该属性在程序中任何地方都可访问。

/**

* 列举系统的属性

* User: leizhimin

* Date: 2008-11-12 21:25:08

*/

public class TestProperty {

        public static void main(String[] args) {

                //获取系统属性

                Properties prop = System.getProperties();

                //输出所有到一个流上，

                prop.list(System.out);

        }

}

执行结果

-- listing properties --

java.runtime.name=Java(TM) SE Runtime Environment

sun.boot.library.path=C:\Program Files\Adobe\Adobe Flash Bu...

java.vm.version=14.2-b01

java.vm.vendor=Sun Microsystems Inc.

java.vendor.url=http://java.sun.com/

path.separator=;

java.vm.name=Java HotSpot(TM) Client VM

file.encoding.pkg=sun.io

user.country=CN

sun.java.launcher=SUN_STANDARD

sun.os.patch.level=Service Pack 3

java.vm.specification.name=Java Virtual Machine Specification

user.dir=D:\workspace\flash_builder_workspace\...

java.runtime.version=1.6.0_16-b01

java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment

java.endorsed.dirs=C:\Program Files\Adobe\Adobe Flash Bu...

os.arch=x86

java.io.tmpdir=C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\

line.separator=

 

java.vm.specification.vendor=Sun Microsystems Inc.

user.variant=

os.name=Windows XP

sun.jnu.encoding=GBK

java.library.path=C:\Program Files\Adobe\Adobe Flash Bu...

java.specification.name=Java Platform API Specification

java.class.version=50.0

sun.management.compiler=HotSpot Client Compiler

os.version=5.1

user.home=D:\我的文档

user.timezone=

java.awt.printerjob=sun.awt.windows.WPrinterJob

file.encoding=UTF-8

java.specification.version=1.6

user.name=Administrator

java.class.path=D:\workspace\flash_builder_workspace\...

java.vm.specification.version=1.0

sun.arch.data.model=32

java.home=C:\Program Files\Adobe\Adobe Flash Bu...

java.specification.vendor=Sun Microsystems Inc.

user.language=zh

awt.toolkit=sun.awt.windows.WToolkit

java.vm.info=mixed mode

java.version=1.6.0_16

java.ext.dirs=C:\Program Files\Adobe\Adobe Flash Bu...

sun.boot.class.path=C:\Program Files\Adobe\Adobe Flash Bu...

java.vendor=Sun Microsystems Inc.

file.separator=\

java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport...

sun.cpu.endian=little

sun.io.unicode.encoding=UnicodeLittle

sun.desktop=windows

sun.cpu.isalist=pentium_pro+mmx pentium_pro pentium+m...

配置格外的jar

D:\workspace\flash_builder_workspace\test_netty_server>java -Djava.ext.dirs=libs

/log -cp bin com.log.test.Test

    -verbose[:class|gc|jni]

                  enable verbose output

-verbose:class

 输出jvm载入类的相关信息，当jvm报告说找不到类或者类冲突时可此进行诊断。

-verbose:gc

 输出每次GC的相关情况。

-verbose:jni

 输出native方法调用的相关情况，一般用于诊断jni调用错误信息。

-version      print product version and exit

java版本信息

    -version:<value>

                  require the specified version to run

    -showversion  print product version and continue

    -jre-restrict-search | -jre-no-restrict-search

                  include/exclude user private JREs in the version search

    -? -help      print this help message

    -X            print help on non-standard options

    -ea[:<packagename>...|:<classname>]

    -enableassertions[:<packagename>...|:<classname>]

                  enable assertions

    -da[:<packagename>...|:<classname>]

    -disableassertions[:<packagename>...|:<classname>]

                  disable assertions

    -esa | -enablesystemassertions

                  enable system assertions

    -dsa | -disablesystemassertions

                  disable system assertions

    -agentlib:<libname>[=<options>]

                  load native agent library <libname>, e.g. -agentlib:hprof

                    see also, -agentlib:jdwp=help and -agentlib:hprof=help

    -agentpath:<pathname>[=<options>]

                  load native agent library by full pathname

    -javaagent:<jarpath>[=<options>]

                  load Java programming language agent, see java.lang.instrument

 

    -splash:<imagepath>

                  show splash screen with specified image

 

C:\Documents and Settings\Administrator>java -version

java version "1.6.0_29"

Java(TM) SE Runtime Environment (build 1.6.0_29-b11)

Java HotSpot(TM) Client VM (build 20.4-b02, mixed mode)