XStream笔记

XStream直接使用流的形式读取XML，并且使用现有的XML解析框架，如DOM等，对XML进行解析后，生成JAVA对象。
默认解析器支持对普通对象的解析，如String ,Date,Collections等，如果需要解析特殊的对象，可以对其Converter接口进行扩展。
详细看XStream官方网站http://xstream.codehaus.org/architecture.html。

例子：

public class User {

    String  name;
    String  age;
    Address address;

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

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

public class Address {

    String code;
    String street;

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

}

    public class XstreamTest {

    XStream xstream;

    public void test() {
        // xstream = new XStream(); // XML转对象时报错 Exception in thread "main" java.lang.IllegalArgumentException: XPP3
        // pull parser library not present. Specify another driver. For example: new
        // XStream(new DomDriver())
        xstream = new XStream(new DomDriver());
        xstream.alias("User", User.class);
        xstream.alias("Address", Address.class);
    }

    public void objToXml() {
        User user = new User();
        user.setName("yaoming");
        user.setAge("30");
        Address address = new Address();
        address.setCode("011101");
        address.setStreet("new york");
        user.setAddress(address);
        System.out.println(xstream.toXML(user));
    }

    public void xmlToObj() {
        StringBuffer buffer = new StringBuffer();
        buffer.append("<User>");
        buffer.append("<name>Tracy McGrady</name>");
        buffer.append("<age>29</age>");
        buffer.append("<address>");
        buffer.append("<code>011101</code>");
        buffer.append("<street>new york</street>");
        buffer.append("</address>");
        buffer.append("</User>");
        User user = (User) xstream.fromXML(buffer.toString());
        System.out.println(user.getName());
    }

    public static void main(String... strings) {
        XstreamTest test = new XstreamTest();
        test.test();
        test.objToXml();
        test.xmlToObj();
    }
}

以上是最基本的例子；


xstream还有其他实用的方法，如不想展现某Collection类型的tag或者忽略掉它，可以使用addImplicitCollection()，本例子里没有用到Collection对象，就不举例子了。还有其他的用法，可以参考API。

使用Converter接口来实现对非普通对象的解析

  public class Child {

    String name;

    public String getName() {
        return name;
    }

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

修改方法：

 public void objToXml() {
        User user = new User();
        user.setName("yaoming");
        user.setAge("30");
        Address address = new Address();
        address.setCode("011101");
        address.setStreet("new york");
        user.setAddress(address);
        Child child = new Child();
        child.setName("baobao");
        user.setChild(child);
        xstream.registerConverter(new ChildValueConverter());
        System.out.println(xstream.toXML(user));
    }

输出：

   <User>
  <name>yaoming</name>
  <age>30</age>
  <address>
    <code>011101</code>
    <street>new york</street>
  </address>
  <child>baobao</child>
</User>