Ajax——XStream

XStream


1. 什么作用
  * 可以把JavaBean转换为（序列化为）xml


2. XStream的jar包
  * 核心JAR包：xstream-1.4.7.jar；
  * 必须依赖包：xpp3_min-1.1.4c（XML Pull Parser，一款速度很快的XML解析器）；


3. 使用步骤
  * XStream xstream = new XStream();
  * String xmlStr = xstream.toXML(javabean);


4. 使用细节
  * 别名：把类型对应的元素名修改了
    > xstream.alias("china", List.class)：让List类型生成的元素名为china
    > xstream.alias("province", Province.class)：让Province类型生成的元素名为province
  * 使用为属性：默认类的成员，生成的是元素的子元素！我们希望让类的成员生成元素的属性
    > xstream.useAttributeFor(Province.class, "name")：把Province类的名为name成员，生成<province>元素的name属性
  * 去除Collection类型的成名：我们只需要Collection的内容，而不希望Collection本身也生成一个元素
    > xstream.addImplicitCollection(Province.class, "cities")：让Province类的名为cities(它是List类型的，它的内容还会生成元素)的成名不生成元素
  * 去除类的指定成名，让其不生成xml元素

    > xstream.omitField(City.class, "description")：在生成的xml中不会出现City类的名为description的对应的元素！

package demo1;

public class City {
	private String name;
	private String description;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getDescription() {
		return description;
	}
	public void setDescription(String description) {
		this.description = description;
	}
	public City(String name, String description) {
		super();
		this.name = name;
		this.description = description;
	}
	public City() {
		super();
		// TODO Auto-generated constructor stub
	}
	
}

package demo1;

import java.util.ArrayList;
import java.util.List;

public class Province {
	private String name;
	private List<City> cities=new ArrayList<City>();
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public List<City> getCities() {
		return cities;
	}
	public void setCities(List<City> cities) {
		this.cities = cities;
	}
	
	public void addCity(City city){
		this.cities.add(city);
	}
	public Province(String name) {
		super();
		this.name = name;
	}
	
}

package demo1;

import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

import com.thoughtworks.xstream.XStream;

public class Demo {
	
	public List<Province> getProinvceList(){
		Province p1=new Province("北京");
		p1.addCity(new City("朝阳区","chaoyang"));
		p1.addCity(new City("西城区","xiCheng"));
		
		Province p2=new Province("内蒙古");
		p2.addCity(new City("呼和浩特","huhehaote"));
		p2.addCity(new City("包头","baotou"));
		
		List<Province> list=new ArrayList<Province>();
		list.add(p1);
		list.add(p2);
		
		return list;
	}
	
	@Test
	public void fun1(){
		List<Province> provinces=getProinvceList();
		/*
		 * 创建XStream对象
		 * 调用toXML把集合转换成xml字符串
		 */
		XStream xstream=new XStream();
		System.out.println(xstream.toXML(provinces));
	}
	
	/*
	 * 别名(alias)
	 * 希望：
	 * * 默认List类型对应<list>元素，希望让List类型对应<china>元素
	 * * 默认Province类型对应<demo1.Province>，希望让它对应<province>
	 * * 默认City类型对应<demo1.City>，希望它对应<city>元素
	 */
	
	@Test
	public void fun2(){
		List<Province> provinces=getProinvceList();
		
		/*
		 * 创建XStream对象
		 * 调用toXML把集合转换成xml字符串
		 */		
		XStream xstream=new XStream();
		xstream.alias("china", List.class);
		xstream.alias("province",Province.class);
		xstream.alias("city", City.class);
		
		System.out.println(xstream.toXML(provinces));
	}
	
	@Test
	public void fun3(){
		List<Province> provinces=getProinvceList();
		
		/*
		 * 创建XStream对象
		 * 调用toXML把集合转换成xml字符串
		 */		
		XStream xstream=new XStream();
		xstream.alias("china", List.class);
		xstream.alias("province",Province.class);
		xstream.alias("city", City.class);
		/*
		 * 把Province类型的name属性，生成<province>元素的属性
		 */
		xstream.useAttributeFor(Province.class, "name");
		
		System.out.println(xstream.toXML(provinces));
	}
	
	/*
	 * 去掉List类型的属性
	 */
	@Test
	public void fun4(){
		List<Province> provinces=getProinvceList();
			
		XStream xstream=new XStream();
		xstream.alias("china", List.class);
		xstream.alias("province",Province.class);
		xstream.alias("city", City.class);
		xstream.useAttributeFor(Province.class, "name");
		/*
		 * 去掉<cities>这样的Collection属性
		 */
		xstream.addImplicitCollection(Province.class, "cities");
		
		System.out.println(xstream.toXML(provinces));
	}
	
	/*
	 * /**
	 * 去除不想要的javabean属性，不生成对应的xml元素！
	 */
	@Test
	public void fun5(){
		List<Province> provinces=getProinvceList();
			
		XStream xstream=new XStream();
		xstream.alias("china", List.class);
		xstream.alias("province",Province.class);
		xstream.alias("city", City.class);
		xstream.useAttributeFor(Province.class, "name");
		xstream.addImplicitCollection(Province.class, "cities");
		
		/*
		 * 让City类的，名为description属性不生成对应的xml元素
		 */
		xstream.omitField(City.class, "description");
		
		System.out.println(xstream.toXML(provinces));
	}
	
	
	
}