Posted on 2007-08-13 10:58
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Jakarta Commons
get set 参考 BeanUtil 包 和 Xpath
http://commons.apache.org/ 的 jxpath
User's Guide
类的加载
JXPathContext context = JXPathContext.newContext( obj );
//和 xpath 的 范围确定
一般取值 存值
String fName = (String)context.getValue("firstName"); //setValue
//参考 http://www.blogjava.net/Good-Game/archive/2007/08/10/135739.html
一般的统计和使用 c 为 list [id,name,.....]
JXPathContext context = JXPathContext.newContext(c);
System.out.println( context.getValue("count( .[name='oo' and id='1' ] )") ); //对象 name=oo 和 id=1的有多少个
System.out.println( context.getValue("sum( .[name='oo' and id='1' ]/id )") );//对象name=oo和id=1的所有id相加
得到集合
Iterator threeBooks = context.iterate("books[position() < 4]");
//xpath 的位置函数 position 其他函数参考 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类属性的 zipCode
xml 在程序 与 xpath 的切入点
<?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");
// 类Container的 属性 locations 头 vendor(xml内) .....
建立 Path工厂 就是 自定义字符串 得到 自定义类
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 类就是 createObject方法中的 Object
//运行解析到 address字符 就进入 if中
建立内参
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]");
// $index 为 3
确定范围 Pointer JXPathContext context = JXPathContext.newContext(bean);
Pointer addressPtr = context.getPointer("/employees[1]/addresses[2]");
JXPathContext relativeContext =
context.getRelativeContext(addressPtr);
String zipCode = (String)relativeContext.getValue("zipCode");
//可以用 xpath 确定范围 很好 呵呵
方法的联系应用
public class Formats {
public static String date(Date d, String pattern){
return new SimpleDateFormat(pattern).format(d);
}
}
context.setFunctions(new ClassFunctions(Formats.class, "format"));
//方法的设置 format
context.getVariables().declareVariable("today", new Date());
String today =
(String)context.getValue("format:date($today, 'MM/dd/yyyy')");
心得： 代码可以写成什么样呢~~ (JXpath)