获取运行中的JVM系统属性

getProperties

public static Properties getProperties()

Determines the current system properties.First, if there is a security manager, its checkPropertiesAccess method is called with no arguments. This may result in a security exception.

The current set of system properties for use by the getProperty(String) method is returned as a Properties object. If there is no current set of system properties, a set of system properties is first created and initialized. This set of system properties always includes values for the following keys:

Key	Description of Associated Value
java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator (“/” on UNIX)
path.separator	Path separator (“:” on UNIX)
line.separator	Line separator (“\n” on UNIX)
user.name	User’s account name
user.home	User’s home directory
user.dir	User’s current working directory

Multiple paths in a system property value are separated by the path separator character of the platform.

Note that even if the security manager does not permit the getProperties operation, it may choose to permit the getProperty(String) operation.

Returns:

the system properties

Throws:

SecurityException – if a security manager exists and its checkPropertiesAccess method doesn’t allow access to the system properties.

See Also:

setProperties(java.util.Properties), SecurityException, SecurityManager.checkPropertiesAccess(), Properties

eclipse wtp project
Eclipse Web Tools Platform (WTP) Project

非常酷的工具集,到底是IBM捐献的,功能异常的强大,不过pre-requirements也是非常之多,eclipse的插件要爆炸了

Developer STRUTS

Check Your Form with Validator

By James Holmes

Enabling the Validator Plug-in

配置Validator插件，也即在配置struts-config.xml，加入该插件

Configuring validator-rules.xml

大多数情况下你不需要修改预定义的验证规则，除非你希望给框架自定义验证规则。

Included Validations

默认情况下已经包含了一些常用的验证器，如required，CreditCard和email等

Creating Form Beans

为了使用验证器，应用中的Form Bean应该是验证器ActionForm的子类，
而不能是ActionFrom本身。这一子类提供了ActionForm的validate()方法的一个实现。Form Bean继承了子类之后并不需要将验证进行硬编码，完全可以将这一方法忽略掉。验证器会帮你提供验证需要的代码。
form bean在struts-config.xml中的配置也同常规的Form Bean相同验证的时候配置validation.xml。两种标准的方式创建Form Bean。一种是创建一个具体的Form Bean，另一种是创建一个动态的Form Bean，validator.xml的Form Bean的验证与struts-config.xml中的Form Bean一对一的绑定，这种机制可以适用于绝大多数的情况，但是当Form Bean在多个Action间复用(可能有的用的字段多一些有的用的少一些)时，就不适用了。为了解决这一问题，验证器有两个子类ValidatorActionForm和DynaValidatorActionForm允许将验证与action进行绑定而不是与Form Bean进行绑定。

Configuring validation.xml

Configuring ApplicationResources.properties

验证器使用Struts的资源束机制来显示错误消息。主要配置ApplicationResource.properties(添加消息文本和对应的key)文件和validation.xml(利用key引用消息文本)文件。

如果不想使用资源束机制的话，也可以在validation.xml文件中直接表明。

Enabling Client-Side Validations

除了服务端的数据验证，Struts还有机制支持客户端验证。
在validator-rules.xml中标明了在客户端用于验证的JavaScript代码(可选的标明)
为了使用客户端验证，就要在每个需要验证的JSP插入Struts HTML标签库的JavaScript标签。而无论是否使用客户端验证，服务端验证都会进行。