Xstream 來實習JavaBean轉換成XML

1. 什麼作用
  * 可以把JavaBean轉換爲（序列化爲）xml

2. XStream的jar包
  * 核心JAR包：xstream-1.4.7.jar；
  * 必須依賴包：xpp3_min-1.1.4c（XML Pull Parser，一款速度很快的XML解析器）；

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

4. 使用細節
  * 別名：把類型對應的元素名修改了
    > xstream.alias("china", List.class)：讓List類型生成的元素名爲china
    > xstream.alias("province", Province.class)：讓Province類型生成的元素名爲province
  * 使用爲屬性：默認類的成員，生成的是元素的子元素！我們希望讓類的成員生成元素的屬性
    > xstream.useAttributeFor(Province.class, "name")：把Province類的名爲name成員，生成<province>元素的name屬性
  * 去除Collection類型的成名：我們只需要Collection的內容，而不希望Collection本身也生成一個元素
    > xstream.addImplicitCollection(Province.class, "cities")：讓Province類的名爲cities(它是List類型的，它的內容還會生成元素)的成名不生成元素
  * 去除類的指定成名，讓其不生成xml元素
    > xstream.omitField(City.class, "description")：在生成的xml中不會出現City類的名爲description的對應的元素！

具體實例

[java] view plain copy

package cn.itcast.demo1;

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

import org.junit.Test;

import com.thoughtworks.xstream.XStream;

/**
 * 演示XStream
 * @author cxf
 *
 */
public class Demo1 {
    // 返回javabean集合
    public List<Province> getProinvceList() {
        Province p1 = new Province();
        p1.setName("北京");
        p1.addCity(new City("東城區", "DongChengQu"));
        p1.addCity(new City("昌平區", "ChangPingQu"));

        Province p2 = new Province();
        p2.setName("遼寧");
        p2.addCity(new City("瀋陽", "shenYang"));
        p2.addCity(new City("葫蘆島", "huLuDao"));

        List<Province> provinceList = new ArrayList<Province>();
        provinceList.add(p1);
        provinceList.add(p2);

        return provinceList;
    }

    /**
<list> --> List類型顯示list
  <cn.itcast.demo1.Province> --> javabean的類型爲Province，它元素的名稱爲類的完整名
    <name>北京</name> --> javabean的屬性名
    <cities> --> javabean的屬性名
      <cn.itcast.demo1.City> --> 類名
        <name>東城區</name> --> 屬性名
        <description>DongChengQu</description> --> 屬性名
      </cn.itcast.demo1.City>
      <cn.itcast.demo1.City>
        <name>昌平區</name>
        <description>ChangPingQu</description>
      </cn.itcast.demo1.City>
    </cities>
  </cn.itcast.demo1.Province>
  <cn.itcast.demo1.Province>
    <name>遼寧</name>
    <cities>
      <cn.itcast.demo1.City>
        <name>瀋陽</name>
        <description>shenYang</description>
      </cn.itcast.demo1.City>
      <cn.itcast.demo1.City>
        <name>葫蘆島</name>
        <description>huLuDao</description>
      </cn.itcast.demo1.City>
    </cities>
  </cn.itcast.demo1.Province>
</list>
     */
    @Test
    public void fun1() {
        List<Province> proList = getProinvceList();
        /*
         * 創建XStream對象
         * 調用toXML把集合轉換成xml字符串
         */
        XStream xstream = new XStream();
        String s = xstream.toXML(proList);
        System.out.println(s);
    }

    /*
     * 別名(alias)
     * 希望：
     * * 默認List類型對應<list>元素，希望讓List類型對應<china>元素
     * * 默認Province類型對應<cn.itcast.demo1.Province>，希望讓它對應<province>
     * * 默認City類型對應<cn.itcast.demo1.City>，希望它對應<city>元素
     */
    /*
<china>
  <province>
    <name>北京</name>
    <cities>
      <city>
        <name>東城區</name>
        <description>DongChengQu</description>
      </city>
      <city>
        <name>昌平區</name>
        <description>ChangPingQu</description>
      </city>
    </cities>
  </province>
  <province>
    <name>遼寧</name>
    <cities>
      <city>
        <name>瀋陽</name>
        <description>shenYang</description>
      </city>
      <city>
        <name>葫蘆島</name>
        <description>huLuDao</description>
      </city>
    </cities>
  </province>
</china>
     */
    @Test
    public void fun2() {
        List<Province> proList = getProinvceList();
        XStream xstream = new XStream();
        /*
         * 給指定的類型指定別名
         */
        xstream.alias("china", List.class);//給List類型指定別名爲china
        xstream.alias("province", Province.class);//給Province指定別名爲province
        xstream.alias("city", City.class);//給City類型指定別名爲city


        String s = xstream.toXML(proList);
        System.out.println(s);
    }

    /*
     * 默認javabean的屬性都會生成子元素，而現在希望生成元素的屬性
     */
/*
<china>
  <province name="北京">
    <cities>
      <city>
        <name>東城區</name>
        <description>DongChengQu</description>
      </city>
      <city>
        <name>昌平區</name>
        <description>ChangPingQu</description>
      </city>
    </cities>
  </province>
  <province name="遼寧">
    <cities>
      <city>
        <name>瀋陽</name>
        <description>shenYang</description>
      </city>
      <city>
        <name>葫蘆島</name>
        <description>huLuDao</description>
      </city>
    </cities>
  </province>
 */
    @Test
    public void fun3() {
        List<Province> proList = getProinvceList();
        XStream xstream = new XStream();
        xstream.alias("china", List.class);//給List類型指定別名爲china
        xstream.alias("province", Province.class);//給Province指定別名爲province
        xstream.alias("city", City.class);//給City類型指定別名爲city


        /*
         * 把Province類型的name屬性，生成<province>元素的屬性
         */
        xstream.useAttributeFor(Province.class, "name");


        String s = xstream.toXML(proList);
        System.out.println(s);
    }


    /*
     * 去除List類型的屬性，只把list中的元素生成xml元素
     */
/*
<china>
  <province name="北京">
    <city>
      <name>東城區</name>
      <description>DongChengQu</description>
    </city>
    <city>
      <name>昌平區</name>
      <description>ChangPingQu</description>
    </city>
  </province>
  <province name="遼寧">
    <city>
      <name>瀋陽</name>
      <description>shenYang</description>
    </city>
    <city>
      <name>葫蘆島</name>
      <description>huLuDao</description>
    </city>
  </province>
</china>
 */
    @Test
    public void fun4() {
        List<Province> proList = getProinvceList();
        XStream xstream = new XStream();
        xstream.alias("china", List.class);//給List類型指定別名爲china
        xstream.alias("province", Province.class);//給Province指定別名爲province
        xstream.alias("city", City.class);//給City類型指定別名爲city
        xstream.useAttributeFor(Province.class, "name");//把Province類型的name屬性，生成<province>元素的屬性


        /*
         * 去除<cities>這樣的Collection類型的屬性
         * 去除Provice類的名爲cities的List類型的屬性！
         */
        xstream.addImplicitCollection(Province.class, "cities");


        String s = xstream.toXML(proList);
        System.out.println(s);
    }

    /**
     * 去除不想要的javabean屬性
     * 就是讓某引起javabean屬性，不生成對應的xml元素！
     */
/*
<china>
  <province name="北京">
    <city>
      <name>東城區</name>
    </city>
    <city>
      <name>昌平區</name>
    </city>
  </province>
  <province name="遼寧">
    <city>
      <name>瀋陽</name>
    </city>
    <city>
      <name>葫蘆島</name>
    </city>
  </province>
</china>
 */
    @Test
    public void fun5() {
        List<Province> proList = getProinvceList();
        XStream xstream = new XStream();
        xstream.alias("china", List.class);//給List類型指定別名爲china
        xstream.alias("province", Province.class);//給Province指定別名爲province
        xstream.alias("city", City.class);//給City類型指定別名爲city
        xstream.useAttributeFor(Province.class, "name");//把Province類型的name屬性，生成<province>元素的屬性
        xstream.addImplicitCollection(Province.class, "cities");//去除Provice類的名爲cities的List類型的屬性！


        /*
         * 讓City類的，名爲description屬性不生成對應的xml元素
         */
        xstream.omitField(City.class, "description");


        String s = xstream.toXML(proList);
        System.out.println(s);
    }
}

文章轉自：http://blog.csdn.net/JOKER_SAMA/article/details/61197689