J2ME System.getProperty標準參數例表。

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J2ME System.getProperty標準參數例表。

The various J2ME JSR documents define system property names that can be queried at runtime. These provide two services:

To indicate the availability of an optional package:

For example, if the device supports the Location API for J2ME then the property microedition.location.version will be present. The value associated with it will be "1.0", to indicate compliance with JSR 179.

To provide platform-dependent configuration data

For instance, the property microedition.commports is present in the MIDP 2.0 specification. Its value is a comma-separated list of ports you can use to build a URL, which the Generic Connection Framework can in turn use to create a javax.microedition.io.CommConnection object.
To query system properties use java.lang.System.getProperty(), as in:

        import        java.lang.*;

        String        value;
        String        key        = "microedition.pim.version";

        value        = System.getProperty( key );
        ...

This table lists the defined system properties, drawing them from JSRs that are in the public review, final ballot, or final state, as defined in the Java Community Process (JCP):

J2ME Defined System Properties

JSR Property Name
Default Value¹
30 microedition.platform null
  microedition.encoding ISO8859_1
  microedition.configuration CLDC-1.0
  microedition.profiles null
37 microedition.locale null
  microedition.profiles MIDP-1.0
75 microedition.io.file.FileConnection.version 1.0
  file.separator (impl-dep)
  microedition.pim.version 1.0
118 microedition.locale null
  microedition.profiles MIDP-2.0
  microedition.commports (impl-dep)
  microedition.hostname (impl-dep)
120 wireless.messaging.sms.smsc (impl-dep)
139 microedition.platform (impl-dep)
  microedition.encoding ISO8859-1
  microedition.configuration CLDC-1.1
  microedition.profiles (impl-dep)
177 microedition.smartcardslots (impl-dep)
179 microedition.location.version 1.0
180 microedition.sip.version 1.0
184 microedition.m3g.version 1.0
185 microedition.jtwi.version 1.0
195 microedition.locale (impl-dep)
  microedition.profiles IMP-1.0
205 wireless.messaging.sms.smsc (impl-dep)
205 wireless.messaging.mms.mmsc (impl-dep)
211 CHAPI-Version 1.0