XStream的基本使用

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先準備兩個bean

1 public class Book {2  private int bookId;3  private String bookName;4  private String bookCode;5 6 ...(get和set方法省略)7 }

 

public class BookShelf {    private int number;    private List<Book> books;    private String remark;    private Date date;    public BookShelf(){        books=new ArrayList<Book>();    }    ...(get和set方法省略)}

使用

 1 Book book1=new Book(); 2 book1.setBookCode("001"); 3 book1.setBookId(1); 4 book1.setBookName("java編程"); 5 Book book2=new Book(); 6 book2.setBookCode("002"); 7 book2.setBookId(2); 8 book2.setBookName("jsp編程"); 9 BookShelf bookShelf=new BookShelf();10 bookShelf.setNumber(1);11 bookShelf.setRemark("第一個書架");12 bookShelf.getBooks().add(book1);13 bookShelf.getBooks().add(book2);14 bookShelf.setDate(new Date());15         16 XStream xStream=new XStream(new DomDriver());17 String str= xStream.toXML(bookShelf);18 System.out.println(str);

輸出結果：

<xml.BookShelf>  <number>1</number>  <books>    <xml.Book>      <bookId>1</bookId>      <bookName>java編程</bookName>      <bookCode>001</bookCode>    </xml.Book>    <xml.Book>      <bookId>2</bookId>      <bookName>jsp編程</bookName>      <bookCode>002</bookCode>    </xml.Book>  </books>  <remark>第一個書架</remark>  <date>2014-07-04 07:03:34.485 UTC</date></xml.BookShelf>

輸出的結果裡，類名轉換為節點名，但前面多了個xml（不爽），時間格式字串也不爽，那下面就來改造一下吧！

1、先處理一下時間格式問題，這個需要我們自己定義date類型的欄位要怎麼轉換，當然xstream為我們提供了介面，實現它吧

public class MuConverter implements Converter {    //判斷欄位是否屬於要轉換的類型   @Override    public boolean canConvert(Class paramClass) {        return Date.class.isAssignableFrom(paramClass);    }    //對象轉化為xml    @Override    public void marshal(Object object, HierarchicalStreamWriter writer,                                    MarshallingContext context) {        SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd");        writer.setValue(format.format(object));    }    //xml轉化為對象   @Override    public Object unmarshal(HierarchicalStreamReader reader,                UnmarshallingContext context) {        try {                  Date date= DateFormat.getInstance().parse(reader.getValue());                  return date;        } catch (ParseException e) {                  return null;        }    }}

2、為各欄位換個名字

xStream.alias("BookShelf", BookShelf.class);xStream.alias("Book", Book.class); //修改節點名稱xStream.aliasField("other", BookShelf.class,"remark");        //欄位不做為節點，而是屬性xStream.aliasAttribute(Book.class, "bookId", "id");xStream.useAttributeFor(Book.class, "bookId");        //去掉集體節點的父節點//xStream.addImplicitCollection(BookShelf.class, "books");        //自訂轉換器xStream.registerConverter(new MuConverter());*/

輸出結果

<BookShelf>  <number>1</number>  <books>    <Book id="1">      <bookName>java編程</bookName>      <bookCode>001</bookCode>    </Book>    <Book id="2">      <bookName>jsp編程</bookName>      <bookCode>002</bookCode>    </Book>  </books>  <other>第一個書架</other>  <date>2014-07-04</date></BookShelf>

3、如果覺得上面的指定代碼太複雜了，也可以使用註解來實現
首先來看兩個bean

@XStreamAlias("Book")public class Book {        @XStreamAlias("id")    @XStreamAsAttribute    private int bookId;    private String bookName;    private String bookCode;       ...    }

@XStreamAlias("BookShelf")public class BookShelf {    private int number;    //去掉集體節點的父節點    //@XStreamImplicit    private List<Book> books;    private String remark;    @XStreamConverter(MuConverter.class)    private Date date;    public BookShelf(){        books=new ArrayList<Book>();    }    ...}

沒有註解的欄位按欄位名預設來轉換
直接調用方法即可

 xStream.autodetectAnnotations(true);//也可以分別調用    //xStream.processAnnotations(BookShelf.class);  //xStream.processAnnotations(Book.class);

 

上面的是對象轉換為xml，現在來實現xml轉換為對象，很簡單（注意：xml轉換成對象，需要通過上面的別名或註解的方式來指明轉換，不能直接調用下面的代碼）

XStream xStream=new XStream(new DomDriver());xStream.autodetectAnnotations(true);BookShelf bookShelf2=(BookShelf)xStream.fromXML(str);

 

序列化和還原序列化支援

不多說，直接上代碼

1、還原序列化

ObjectInputStream input=xStream.createObjectInputStream(inputStream);BookShelf bookShelf=(BookShelf)input.readObject();

2、序列化

ObjectOutputStream out=xstream.createObjectOutputStream(outputStream);out.writeObject(bookShelf);out.close();

3、PrettyPrintWriter、CompactWriter
這兩個是XStream內建的用於輸出xml檔案，區別在於後者輸出的xml是串連的，前者輸出的是有格式的xml