Xstream 自定义converter

1、创建一个Person转换器：
下面我们来创建一个简单的转换器，它能：
a，用来转换Person类
b，将Person实例转换成XML
c，将xml转换为Person实例
（1）首先创建一个PersonConverter类，并让这个类实现Converter接口：

package com.thoughtworks.xstream.examples; 
import com.thoughtworks.xstream.converters.Converter; 
import com.thoughtworks.xstream.converters.MarshallingContext; 
import com.thoughtworks.xstream.converters.UnmarshallingContext; 
import com.thoughtworks.xstream.io.HierarchicalStreamReader; 
import com.thoughtworks.xstream.io.HierarchicalStreamWriter; 
public class PersonConverter implements Converter { 
        public boolean canConvert(Class clazz) { 
                return false; 
        } 
        public void marshal(Object value, HierarchicalStreamWriter writer, 
                        MarshallingContext context) { 
        } 
        public Object unmarshal(HierarchicalStreamReader reader, 
                        UnmarshallingContext context) { 
                return null; 
        } 
}

 

（2） 下面，我们首先告诉转换器，我们只能转换Person类，而不是别的类，包括其子类：（这一步很简单，除非你是用来处理泛型的转换器是会困难一点。）

public boolean canConvert(Class clazz) { 
        return clazz.equals(Person.class); 
}

 （3）编辑转换器

 

 

 

 

 

package com.thoughtworks.xstream.examples; 
import com.thoughtworks.xstream.converters.Converter; 
import com.thoughtworks.xstream.converters.MarshallingContext; 
import com.thoughtworks.xstream.converters.UnmarshallingContext; 
import com.thoughtworks.xstream.io.HierarchicalStreamReader; 
import com.thoughtworks.xstream.io.HierarchicalStreamWriter; 
public class PersonConverter implements Converter { 
 
        public boolean canConvert(Class clazz) { 
                return clazz.equals(Person.class); 
        } 
	    /**
		**Marshal方法是用来将对象转换为XML的，他有三个参数：
			1，我们准备转换的对象
			2，我们准备输出对象的writer
			3，当前的marshaling context
		*/
        public void marshal(Object value, HierarchicalStreamWriter writer, 
                        MarshallingContext context) { 

                Person person = (Person) value; 
				//创建一个叫做fullname的节点，并将person的名字传给他
				//可以任意次数的调用start/end node方法，但需要记住，你必须在打开一个节点之后记住关闭它。
				//一般来说，执行转换的操作在setValue方法调用时发生
                writer.startNode("fullname"); 
                writer.setValue(person.getName()); 				
                writer.endNode(); 
        } 
 
        public Object unmarshal(HierarchicalStreamReader reader, 
                        UnmarshallingContext context) { 
                Person person = new Person(); 
				//使用moveDown和moveUp方法在节点树层次中移动，所以，这里我们只需要简单的moveDown，得到值，再moveUp
                reader.moveDown(); 
                person.setName(reader.getValue()); 
                reader.moveUp(); 
                return person; 
        } 
}

 （4）注册转换器

XStream xStream = new XStream(new DomDriver()); 
                xStream.registerConverter(new PersonConverter()); 

 

 

 

 

 

 

2、Date转换器示例：

 

package com.thoughtworks.xstream.examples; 
 
import java.text.DateFormat; 
import java.text.ParseException; 
import java.util.Calendar; 
import java.util.Date; 
import java.util.GregorianCalendar; 
import java.util.Locale; 
import com.thoughtworks.xstream.converters.ConversionException; 
import com.thoughtworks.xstream.converters.Converter; 
import com.thoughtworks.xstream.converters.MarshallingContext; 
import com.thoughtworks.xstream.converters.UnmarshallingContext; 
import com.thoughtworks.xstream.io.HierarchicalStreamReader; 
import com.thoughtworks.xstream.io.HierarchicalStreamWriter; 
public class DateConverter implements Converter { 
        private Locale locale; 
        public DateConverter(Locale locale) { 
                super(); 
                this.locale = locale; 
        } 
        public boolean canConvert(Class clazz) { 
                return Calendar.class.isAssignableFrom(clazz); 
        } 
        public void marshal(Object value, HierarchicalStreamWriter writer, 
                        MarshallingContext context) { 
                Calendar calendar = (Calendar) value; 
                Date date = calendar.getTime(); 
                DateFormat formatter = DateFormat.getDateInstance(DateFormat.FULL, 
                                this.locale); 
                writer.setValue(formatter.format(date)); 
        } 
        public Object unmarshal(HierarchicalStreamReader reader, 
                        UnmarshallingContext context) { 
                GregorianCalendar calendar = new GregorianCalendar(); 
				//时间本地化
                DateFormat formatter = DateFormat.getDateInstance(DateFormat.FULL, 
                                this.locale); 
                try { 
                        calendar.setTime(formatter.parse(reader.getValue())); 
                } catch (ParseException e) { 
                        throw new ConversionException(e.getMessage(), e); 
                } 
                return calendar; 
        } 
}


// grabs the current date from the virtual machine 
Calendar calendar = new GregorianCalendar(); 
// creates the xstream 
XStream xStream = new XStream(new DomDriver()); 
// brazilian portuguese locale 
xStream.registerConverter(new DateConverter(new Locale("pt", "br"))); 
// prints the result 
System.out.println(xStream.toXML(calendar)); 

 

评论

2 楼 zhjxzhj 2012-01-09  

正需要这个  非常感谢

1 楼 zhjxzhj 2012-01-09  

很牛逼   非常感谢