Skynet

JXPathContext?context?=?JXPathContext.newContext( obj );
//和 xpath 的 范圍確定

一般取值 存值  
String?fName?=?(String)context.getValue("firstName"); //setValue
//參考 http://www.aygfsteel.com/Good-Game/archive/2007/08/10/135739.html

一般的統計和使用  c  為 list [id,name,.....]

????????JXPathContext?context?=?JXPathContext.newContext(c);
??????? System.out.println(?context.getValue("count(?.[name='oo'?and?id='1'?]?)")?); //對象 name=oo 和 id=1的有多少個
        System.out.println( context.getValue("sum( .[name='oo' and id='1' ]/id )") );//對象name=oo和id=1的所有id相加





得到集合
?Iterator?threeBooks?=?context.iterate("books[position()?<?4]");
//xpath 的位置函數 position 其他函數參考 http://www.w3.org/TR/xpath  
//4 Core Function Library

xpath 使用
public?class?Employee?{
????private?Map?addressMap?=?new?HashMap();
????{
????????addressMap.put("home",?new?Address());
????????addressMap.put("office",?new?Address());
????}
????public?Map?getAddresses(){
???????return?addressMap;
????}
????
?}
?String?homeZipCode?=?(String)context.?getValue("addresses[@name='home']/zipCode");
//使用的是 addressMap map 的 key = home 的Address類屬性的 zipCode

xml 在程序 與 xpath 的切入點 
????<?xml?version="1.0"??>
????<vendor>
??????<location?id="store101">
????????<address>
??????????<street>Orchard?Road</street>
????????</address>
??????</location>

??????<location?id="store102">
????????<address>
??????????<street>Tangerine?Drive</street>
????????</address>
??????</location>
????</vendor>

class?Company?{
????private?Container?locations?=?null;

????public?Container?getLocations(){
????????if?(locations?==?null){
????????????URL?url?=?getClass().getResource("Vendor.xml");
????????????locations?=?new?XMLDocumentContainer(url);
????????}
????????return?locations;
????}
?}
?
?context?=?JXPathContext.newContext(new?Company());
?
?String?street?=?(String)context.getValue(
????????????????"locations/vendor/location[@id?=?'store102']//street");
// 類Container的 屬性 locations 頭 vendor(xml內) .....

建立 Path工廠 就是 自定義字符串 得到 自定義類
?public?class?AddressFactory?extends?AbstractFactory?{
????public?boolean?createObject(JXPathContext?context,?Pointer?pointer,
????????????????????????????????Object?parent,?String?name,?int?index){
?????if?((parent?instanceof?Employee)?&&?name.equals("address"){
???????((Employee)parent).setAddress(new?Address());
???????return?true;
?????}
?????return?false;
???}
?}

?JXPathContext?context?=?JXPathContext.newContext(emp);
?context.setFactory(new?AddressFactory());
?context.createPath("address");
?context.createPathAndSetValue("address/zipCode",?"90190");
// emp 類就是 createObject方法中的 Object
//運行解析到 address字符 就進入 if中

建立內參
?JXPathContext?context?=?JXPathContext.newContext(auth);
?context.getVariables().declareVariable("index",?new?Integer(2));
 context.setValue("$index", new Integer(3));
?Book?secondBook?=?(Book)context.getValue("books[$index]");
// $index 為 3 

確定范圍 Pointer?
 JXPathContext?context?=?JXPathContext.newContext(bean);
?Pointer?addressPtr?=?context.getPointer("/employees[1]/addresses[2]");
?JXPathContext?relativeContext?=?
??????????????context.getRelativeContext(addressPtr);
?String?zipCode?=?(String)relativeContext.getValue("zipCode");
//可以用 xpath 確定范圍 很好 呵呵

方法的聯系應用
?public?class?Formats?{
????public?static?String?date(Date?d,?String?pattern){
????????return?new?SimpleDateFormat(pattern).format(d);
????}
????
?}??????????????????????????????????????????????????? ?
?context.setFunctions(new?ClassFunctions(Formats.class,?"format"));
 //方法的設置 format 
?
?context.getVariables().declareVariable("today",?new?Date());
?String?today?=
?????(String)context.getValue("format:date($today,?'MM/dd/yyyy')");


心得： 代碼可以寫成什么樣呢~~ (JXpath)