通用联接框架（GCF）连接类型使用总结

通用连接框架（Generic Connection Framework,GCF）是在J2ME平台中广泛使用的用于联网和IO处理的类。本文主要讲述GCF的关键特性，然后把各种连接的关键信息总结为列表的形式，供开发者在使用GCF的时候参考。

使用GCF建立连接的方式类似下面程序片断：

    ...

    import Java.lang.String;

    import javax.microedition.io.*;

    static Connection Connector.open( String name );

    ...

我们关注的主要是Connection和name参数，下面解释什么是name?什么是Connection。Name实际上是与Connection关联的URI。形式如：

scheme : [address] [params]

其中scheme是协议的名称，比如http；address是指定协议的连接端点；params是一些可选的参数，形式类似于language=Chinese。我们给出一个例子：http://www.j2medev.com/servlet?hello=world。

在介绍Connection之前，我们有必要说明一下MIDP规范中说明的一个问题，那就是设备支持什么协议。在MIDP规范中，协议支持的分类共三种：必须，推荐和可选。http和https是MIDP规范要求设备必须支持的，其他的协议都列入了推荐和可选类别中。在其他的可选包中通常也会用到GCF的扩展，比如WMA使用了MessageConnection，JSR75使用了FileConnection。我们可以通过查询系统属性的方式来检查设备是否支持相关的协议连接。比如，我们可能使用下面的方法查询设备对jsr75的支持情况：

...

    import java.lang.System;

    import java.lang.String;

    String name = "microedition.io.file.FileConnection.version";

    String value = System.getProperty( name );

    Boolean hasFile;

    if ( ( value != null ) && value.equals( "1.0" ) )

        hasFile = true;

    else

        hasFile = false;

...

    在使用GCF的时候，我们首先应该根据项目需求选择适当的Connection。关于Connection的层次结构可以从下图清晰的了解到,

    下面的部分总结了GCF支持的连接类型，这些信息按照接口、BNF语法和例子来分组，供开发者参考：

MIDP2.0(JSR 118)

串口连接

支持: 可选

接口: javax.microedition.io.CommConnection，扩展了StreamConnection

BNF:

    url          ::== "comm:" port_id *(option_list)

    port_id      ::== 1*(characters)

    option_list  ::== *(baudrate bitsperchar stopbits parity blocking

                       autocts autorts)

    baudrate     ::== ";baudrate=" digits

    bitsperchar  ::== ";bitsperchar=" bit_value

    bit_value    ::== "7" "8"

    stopbits     ::== ";stopbits=" stop_value

    stop_value   ::== "1" "2"

    parity       ::== ";parity=" parity_value

    parity_value ::== "even" "odd" "none"

    blocking     ::== ";blocking=" on_off

    autocts      ::== ";autocts=" on_off

    autorts      ::== ";autorts=" on_off

    on_off       ::== "on" "off"

例子:

    "comm:0;bitsperchar=8;stopbits=1;parity=none"

    "IR1"

可以使用下面的方法列出port_id的值：

    import java.lang.System;

    import java.lang.String;

    String ports = System.getProperty( "microedition.commports" );

--------------------------------------------------------------------------------

HTTP连接

支持: 必须

接口: javax.microedition.io.HttpConnection ，扩展了ContentConnection

定义: IETF RFC 1738, Section 3.3 HTTP

例子:

    "http://java.sun.com"

    "http://www.sun.com:80"

--------------------------------------------------------------------------------

HTTPS Connection

支持: 必须

接口: javax.microedition.io.HttpsConnection，扩展了HttpConnection

例子:

    "https://java.sun.com"

    "https://www.sun.com:443"

--------------------------------------------------------------------------------

安全连接

支持: 推荐

接口: javax.microedition.io.SecureConnection ，扩展了SocketConnection

BNF:

    url       ::== "ssl://" hostport

    hostport  ::== host ":" port

    host      ::== host name or IP address

    port      ::== numeric port number

例子:

    "ssl://www.sun.com"

    "ssl://java.sun.com:443"

注意: 只支持客户端模式，设备上不支持服务器模式

--------------------------------------------------------------------------------

Server Socket Connection

支持: 推荐

接口: javax.microedition.io.ServerSocketConnection ，扩展了StreamConnectionNotifier

BNF:

    url       ::== "socket://" "socket://" hostport

    hostport  ::== host ":" port

    host      ::== omitted for inbound connections

    port      ::== numeric port number (omitted for system assigned port)

例子:

    "socket://:25"

    "socket://:17"

    "socket://"

--------------------------------------------------------------------------------

Socket Connection

支持: 推荐

接口: javax.microedition.io.SocketConnection ，扩展了StreamConnection

BNF:

    url       ::== "socket://" hostport

    hostport  ::== host ":" port

    host      ::== host name or IP address (omitted for inbound connections)

    port      ::== numeric port number

例子:

    "socket://developer.sun.com/techtopics/mobility:80"

    "socket://www.sun.com:53"

--------------------------------------------------------------------------------

Datagram Connection

支持: 推荐

接口: javax.microedition.io.UDPDatagram.Connection ，扩展了DatagramConnection

BNF:

    url       ::== "datagram://" "datagram://" hostport

    hostport  ::== host ":" port

    host      ::== host name or IP address (omitted for inbound connections)

    port      ::== numeric port number (omitted for system assigned port)

例子:

    "datagram://"                - server with system assigned port

    "datagram://:7"              - server with specified port

    "datagram://java.sun.com:80" - client

JSR 75 PDA Optional Packages

查询方式: System.getProperty( "microedition.io.file.FileConnection.version" ).equals( "1.0" );

接口: javax.microedition.io.file.FileConnection ，扩展了StreamConnection

定义: IETF RFC 1738, Section 3.10 Files

例子:

    "file:///CFCard/music/thewayup/opening.mp3"

    "file:///RWM/photos/emma.jpg"

    "file://localhost/RWM/photos/thekids.jpg"

JSR 82 Java APIs for Bluetooth Wireless Technology, version 1.0a

 是否支持蓝牙只能通过尝试的方式得到了。

Serial Port Profile (SPP)

接口: javax.microedition.io.StreamConnection

接口: javax.microedition.io.StreamConnectionNotifier

BNF:

    url          ::== srvString cliString

    srvString    ::== "BTspp" ":" "//" srvHost 0*5(srvParams)

    cliString    ::== "btspp" ":" "//" cliHost 0*3(cliParams)

    cliHost      ::== btAddress ":" channel

    srvHost      ::== "localhost" ":" uuid

    channel      ::== %d1-30

    uuid         ::== 1*32(HEXDIG)

    bool         ::== "true" "false"

    btAddress    ::== 12*12(HEXDIG)

    text         ::== 1*( ALPHA DIGIT " " "-" "_" )

    HEXDIG       ::== "A".."F" "a".."f" "0".."9"

    ALPHA        ::== "A".."Z" "a".."z"

    DIGIT        ::== "0".."9"

    name         ::== ";name=" text

    master       ::== ";master=" bool

    encrypt      ::== ";encrypt=" bool

    authorize    ::== ";authorize=" bool

    authenticate ::== ";authenticate=" bool

    cliParams    ::== master encrypt authenticate

    srvParams    ::== name master encrypt authorize authenticate

例子:

    "btspp://000a95020c7b:5;name=SPPex"

    "btspp://localhost:8CDF20D5A6B711D99042000A95BDA676;name=SPPex"

--------------------------------------------------------------------------------

Logical Link Control and Adaptation Profile (L2CAP)

接口: javax.bluetooth.L2CAPConnection ，扩展了Connection

接口: javax.bluetooth.L2CAPConnectionNotifier ，扩展了Connection

BNF:

    url          ::== srvString cliString

    srvString    ::== "btl2cap" ":" "//" srvHost 0*7(srvParams)

    cliString    ::== "btl2cap" ":" "//" cliHost 0*5(cliParams)

    cliHost      ::== address ":' psm

    srvHost      ::== "localhost" ":" uuid

    psm          ::== 4*4(HEXDIG)

    receiveMTU   ::== ";receiveMTU=" 1*(DIGIT)

    transmitMTU  ::== ";transmitMTU=" 1*(DIGIT)

    cliParams    ::== master encrypt authenticate receiveMTU transmitMTU

    srvParams    ::== name master encrypt authorize authenticate

                        receiveMTU transmitMTU

例子:

    "btl2cap://000a95020c7b:5;name=sync l2cap"

    "btl2cap://localhost:8CDF20D5A6B711D99042000A95BDA676;name=sync l2cap"

--------------------------------------------------------------------------------

Object Exchange Protocol (OBEX)

接口: javax.obex.SessionNotifier ，扩展了Connection

接口: javax.obex.ClientSession ，扩展了Connection

接口: javax.obex.Operation ，扩展了ContentConnection

BNF:

    url           ::== tcpObex irdaObex btObex

    btObex        ::== btSrvString btCliString

    tcpObex       ::== tcpSrvString tcpCliString

    irdaObex      ::== irdaSrvString irdaCliString

    tcpCliString  ::== "tcpobex" ":" "//" tcpHost

    tcpSrvString  ::== "tcpobex" ":" "//" 0*1(ipPort)

    ipPort        ::== 1*(DIGIT)

    ipAddress     ::== 3*3(%d0-255 ".") (%d0-255)

    ipName        ::== 1*( hostLabel "." ) topLabel

    topLabel      ::== ALPHA ALPHA *(alphaNum "-") alphaNum

    hostLabel     ::== alphaNum alphaNum *(alphaNum "-") alphaNum

    tcpHost       ::== ipName 0*1(":" ipPort) ipAddress 0*1(colon ipPort)

    btSrvString   ::== "btgoep" ":" "//" btSrvHost 0*5(btSrvParams)

    btCliString   ::== "btgoep" ":" "//" btCliHost 0*3(btCliParams)

    btCliParams   ::== master encrypt authenticate

    btSrvParams   ::== name master encrypt authorize authenticate

    btCliHost     ::== btAddress ":" channel

    btSrvHost     ::== "localhost" ":" uuid

    irdaSrvString ::== "irdaobex" ":" "//" irdaSrvHost 0*1(irdaParams)

    irdaCliString ::== "irdaobex" ":" "//" irdaCliHost 0*1(irdaParams)

    irdaSrvHost   ::== "localhost" 0*1("." 1*(DIGIT))

    irdaCliHost   ::== "discover" 0*1("." 1*(DIGIT))

                       "addr." 2*8(HEXDIG)

                       "conn"

                       "name." 1*(characters)

    irdaParams    ::== ";ias=" 1*(characters) 0*("," 1*(characters))

    characters    ::== %d0-255

    alphaNum      ::== ALPHA DIGIT

例子:

    "tcpobex://litespeed:6512"

    "tcpobex://:6512"

    "btgoep://000a95020c7b:996"

    "btgoep://localhost:8CDF20D5A6B711D99042000A95BDA676;name=playlist"

    "irdaobex://discover.08;ias=fax"

    "irdaobex://localhost.08;ias=fax,OBEX,OBEX:IrXfer"

JSR 120 Wireless Messaging API (WMA), version 1.1

查询方式: System.getProperty( "wireless.messaging.sms.smsc" ) != null

接口: javax.wireless.messaging.MessageConnection ，扩展了Connection

BNF:

    url                  ::== "sms://" address_part

    address_part         ::== foreign_host_address local_host_address

    local_host_address   ::== port_number_part

    port_number_part     ::== ":" digits

    foreign_host_address ::== msisdn msisdn port_number_part

    msisdn               ::== "+" digits digits

    digits               ::== DIGIT DIGIT digits

例子:

    "sms://+19055551212"

    "sms://+14165551212:5009"

    "sms://:5009"

--------------------------------------------------------------------------------

GSM Cell Broadcast Adapter

接口: javax.wireless.messaging.MessageConnection ，扩展了Connection

BNF:

    url                     ::== "cbs://" address_part

    address_part            ::== message_identifier_part

    message_identifier_part ::== ":" digits

    digits                  ::== DIGIT DIGIT digits

例子:

    "cbs://:5009"

    "cbs://:1089"

JSR 205 Wireless Messaging API (WMA), version 2.0

查询方式: System.getProperty( "wireless.messaging.mms.mmsc" ) != null

接口: javax.wireless.messaging.MessageConnection ，扩展了Connection

BNF:

    url                   ::== "mms://" address_part

    address_part          ::== (e-mail-address device-address shortcode-address

                               application-id)

    device-address        ::== general-phone-address [application-id]

    general-phone-address ::== (global-telephone-type "/TYPE=PLMN")

                               (ipv4 "/TYPE=IPv4")

                                (ipv6 "/TYPE=IPv6")

                               (escaped value "/TYPE=" address-type)

    global-telephone-type ::== "+" *(DIGIT)

    ipv6                  ::== IETF RFC 1884

    ipv4                  ::== 1 *DIGIT "." 1*DIGIT "." 1*DIGIT "." 1*DIGIT

    application-id        ::== ":" [("com" "org" "edu" "gov")] [organization] [*(package-name)] class-name

    organization          ::== "." *applicationID-symbol

    package-name          ::== "." *applicationID-symbol

    class-name            ::== "." *applicationID-symbol

    address-type          ::== *address-char

    address-char          ::== *(ALPHA DIGIT "_")

    e-mail-address        ::== mailbox group

    group                 ::== phrase "." [#mailbox] ";"

    phrase                ::== *(space Word space)

    mailbox               ::== addr-spec [phrase] route-addr

    route-addr            ::== "<" [route] addr-spec ">"

    route                 ::== 1#("@" domain) ":"

    addr-spec             ::== local-part "@" domain

    local-part            ::== word *("." word)

    domain                ::== sub-domain *("." sub-domain)

    sub-domain            ::== domain-ref domain-literal

    domain-ref            ::== atom

    domain-literal        ::== "[" *(dtext quoted-pair) "]"

    atom                  ::== ALPHA DIGIT "!" "#" "$" "%" "'" "*"

                               "+" "-" "=" "?" "{" "}" "" "~"

                               "^" "_"

    word                  ::== atom quoted-string

    quoted-string         ::== '"' (qtext qpair) *endq"

    qtext                 ::== (^'"')["\"]

    endq                  ::== [^"\\"]

    space                 ::== *(" ")

    qpair                 ::== "\\."

    shortcode-address     ::== shortcode-string

    shortcode-string      ::== *(ALPHA DIGIT "!" '"' "$" "%" "&"

                               "/" "(" ")" "+" "*" "." "-"

                               "/" "=" "< ">" "[" "]" "_"

                               "^" "?" "{" "}" "'" "~" ";"

    applicationID-symbol  ::== ALPHA DIGIT "." "_"

例子:

    "mms://+14165552112"

    "mms://richard@sun.com"

    "mms://+16475551212:com.sun.wireless.photo"

    "mms://:com.sun.wireless.voicenote"

原文请参考这里

（出处：）