使用XStream進行POJO和xml之間的轉(zhuǎn)換

XStream是一個開源項目，利用它可以方便的進行java對象和xml之間進行轉(zhuǎn)換，從而在測試，服務器設置等方面有很好的應用。

先建兩個java對象

1.Adress類

package ?xml_chb;

public ? class ?Adress? ... {
???? private ?String?provice;
???? private ?String?city;
???? public ?String?getCity()? ... {
???????? return ?city;
????}
???? public ? void ?setCity(String?city)? ... {
???????? this .city? = ?city;
????}
???? public ?String?getProvice()? ... {
???????? return ?provice;
????}
???? public ? void ?setProvice(String?provice)? ... {
???????? this .provice? = ?provice;
????}
}

?2.Person類

package ?xml_chb;

public ? class ?Person? ... {

???? private ?String?name = "" ;
???? private ?String?sex = "" ;
???? private ? int ?age;
???? private ?String?mobile;
???? private ?Adress?adress;
????
???? public ? int ?getAge()? ... {
???????? return ?age;
????}

???? public ? void ?setAge( int ?age)? ... {
???????? this .age? = ?age;
????}

???? public ?String?getMobile()? ... {
???????? return ?mobile;
????}

???? public ? void ?setMobile(String?mobile)? ... {
???????? this .mobile? = ?mobile;
????}

???? public ?String?getName()? ... {
???????? return ?name;
????}

???? public ? void ?setName(String?name)? ... {
???????? this .name? = ?name;
????}

???? public ?String?getSex()? ... {
???????? return ?sex;
????}

???? public ? void ?setSex(String?sex)? ... {
???????? this .sex? = ?sex;
????}

???? public ?Adress?getAdress()? ... {
???????? return ?adress;
????}

???? public ? void ?setAdress(Adress?adress)? ... {
???????? this .adress? = ?adress;
????}

}

3.生成一個Person對象，并將其轉(zhuǎn)化為xml

//生成一個java對象
??Person person=new Person();
??person.setName("chb");
??person.setAge(22);
??person.setSex("boy");
??
??//生成一個Adress對象
??Adress adr=new Adress();
??adr.setProvice("Beijing");
??adr.setCity("Beijing");
??person.setAdress(adr);
??
??//將java對象轉(zhuǎn)化為xml
??XStream xstream=new XStream(new DomDriver());
??String strxml=xstream.toXML(person);
??System.out.println(strxml);

輸出：

< xml__chb .Person >
?? < name > chb </ name >
?? < sex > boy </ sex >
?? < age > 22 </ age >
?? < adress >
???? < provice > Beijing </ provice >
???? < city > Beijing </ city >
?? </ adress >
</ xml__chb.Person >

我們可以看到，xml根結(jié)點是<xml_chb.Person>是類的全名，這樣看起來很繁瑣，我們可以使用別名來改進這一現(xiàn)象：

? xstream.alias("person",Person.class);
??strxml=xstream.toXML(person);
??System.out.println(strxml);

輸出結(jié)果為：

< person >
?? < name > chb </ name >
?? < sex > boy </ sex >
?? < age > 22 </ age >
?? < adress >
???? < provice > Beijing </ provice >
???? < city > Beijing </ city >
?? </ adress >
</ person >

4.從xml轉(zhuǎn)化為POJO

String str="<person><name>emily</name><sex>girl</sex><age>22</age><adress><provice>Beijing</provice><city>Beijing</city></adress></person>";
??Person person1=(Person)xstream.fromXML(str);
??System.out.println("姓名："+person1.getName());
??System.out.println("性別："+person1.getSex());

輸出結(jié)果為：

姓名：emily
性別：girl

5.修改元素值

Adress adr1=new Adress();
??adr1.setProvice("Shanghai");
??adr1.setCity("Shanghai");
??person.setAdress(adr1);
??strxml=xstream.toXML(person);
??System.out.println(strxml);

輸出結(jié)果：

< person >
?? < name > chb </ name >
?? < sex > boy </ sex >
?? < age > 22 </ age >
?? < adress >
???? < provice > Shanghai </ provice >
???? < city > Shanghai </ city >
?? </ adress >
</ person >

XStream的jar包可以直接到http://xstream.codehaus.org/下載，那里有一些簡單例子

XStream是個很小的開源項目，所以它能實現(xiàn)的功能也就很有限，它只能包裝簡單類型的元素進行轉(zhuǎn)換，復雜類型的，比如Calendar,Date等類型則需要用戶自己實現(xiàn)Converter。

還有，XStream對xml的操作并不好，比如想把一個子節(jié)點變成屬性就是一個很復雜的工作，但是大家平時用于測試的話，看看對象中到底存著什么數(shù)據(jù)，還是必要的。