XStream的作用
XStream可以把JavaBean对象转换成xml文件。通常服务器给客户端响应的数据是来自数据库的一组对象，这时通过把对象转化成xml再响应给客户端，可以使用XStream。
XSteam具体使用
XSteam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）；
使用步骤
XStream xstream = new XStream();
String xmlStr = xstream.toXML(javabean);
使用细节：
设置别名：xstream.alias(别名, 类)
将子元素设置成属性：xstream.useAttributeFor(类名, 子元素名)
去除Collection类型的标签名： xstream.addImplicitCollection(类名, 元素名)
去除指定类名，不生成对应的xml元素：xstream.omitField(类名, 元素名)
具体代码示例
建立两个javabean：City.java和Province.java
public class City {
String name;//城市名
String description;//城市描述
public City(){
}
public City(String name,String description){
this.name=name;
this.description=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;
}
}Province.java
public class Province {
String name;//省份名
List<City> arrayList=new ArrayList<>();
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<City> getArrayList() {
return arrayList;
}
public void setArrayList(List<City> arrayList) {
this.arrayList = arrayList;
}
public void addCity(City city){
arrayList.add(city);
}
}
测试类：XStreamTest.java
public class XStreamTest {
public List<Province> getProvince(){
List<Province> provinceList=new ArrayList<>();
Province province1=new Province();
province1.setName("北京");
City city1=new City("海淀区","haidianQu");
City city2=new City("西土城区","xituchengQu");
province1.addCity(city1);
province1.addCity(city2);
Province province2=new Province();
province2.setName("安徽");
City city3=new City("合肥市","hefei");
City city4=new City("蚌埠市","bengbu");
province2.addCity(city3);
province2.addCity(city4);
provinceList.add(province1);
provinceList.add(province2);
return provinceList;
}
/**
* 无任何处理，得到的xml
* <list>
* <cn.edu.stu.web.servlet.Province>
* <name>北京</name>
* <arrayList>
* <cn.edu.stu.web.servlet.City>
* <name>海淀区</name>
* <description>haidianQu</description>
* </cn.edu.stu.web.servlet.City>
* <cn.edu.stu.web.servlet.City>
* <name>西土城区</name>
* <description>xituchengQu</description>
* </cn.edu.stu.web.servlet.City>
* </arrayList>
* </cn.edu.stu.web.servlet.Province>
* <cn.edu.stu.web.servlet.Province>
* <name>安徽</name>
* <arrayList>
* <cn.edu.stu.web.servlet.City>
* <name>合肥市</name>
* <description>hefei</description>
* </cn.edu.stu.web.servlet.City>
* <cn.edu.stu.web.servlet.City>
* <name>蚌埠市</name>
* <description>bengbu</description>
* </cn.edu.stu.web.servlet.City>
* </arrayList>
* </cn.edu.stu.web.servlet.Province>
* </list>
*/
@Test
public void func1(){
//得到省份list
List<Province>provinceList=getProvince();
//创建XSTream对象
XStream xStream=new XStream();
//得到省份对象的xml
String s=xStream.toXML(provinceList);
System.out.println(s);
}
/**
*
* 将<list> 替换成<china>
* <cn.edu.stu.web.servlet.Province>替换成<province>
* <cn.edu.stu.web.servlet.City>替换成<city>
*
* <china>
* <province>
* <name>北京</name>
* <arrayList>
* <city>
* <name>海淀区</name>
* <description>haidianQu</description>
* </city>
* <city>
* <name>西土城区</name>
* <description>xituchengQu</description>
* </city>
* </arrayList>
* </province>
* <province>
* <name>安徽</name>
* <arrayList>
* <city>
* <name>合肥市</name>
* <description>hefei</description>
* </city>
* <city>
* <name>蚌埠市</name>
* <description>bengbu</description>
* </city>
* </arrayList>
* </province>
* </china>
*/
@Test
public void func2(){
//得到省份list
List<Province>provinceList=getProvince();
//创建XSTream对象
XStream xStream=new XStream();
//将生成的xml内容对应的标签替换别名
xStream.alias("china",List.class);
xStream.alias("province",Province.class);
xStream.alias("city",City.class);
//得到省份对象的xml
String s=xStream.toXML(provinceList);
System.out.println(s);
}
/**
* 隐藏掉省份中的城市集合属性
*
* <china>
* <province>
* <name>北京</name>
* <city>
* <name>海淀区</name>
* <description>haidianQu</description>
* </city>
* <city>
* <name>西土城区</name>
* <description>xituchengQu</description>
* </city>
* </province>
* <province>
* <name>安徽</name>
* <city>
* <name>合肥市</name>
* <description>hefei</description>
* </city>
* <city>
* <name>蚌埠市</name>
* <description>bengbu</description>
* </city>
* </province>
* </china>
*/
@Test
public void func3(){
//得到省份list
List<Province>provinceList=getProvince();
//创建XSTream对象
XStream xStream=new XStream();
//将生成的xml内容对应的标签替换别名
xStream.alias("china",List.class);
xStream.alias("province",Province.class);
xStream.alias("city",City.class);
//隐藏掉省份中的城市集合属性
xStream.addImplicitCollection(Province.class,"arrayList");
//得到省份对象的xml
String s=xStream.toXML(provinceList);
System.out.println(s);
}
/**
* 把province类的成员，变成province标签的属性
* <china>
* <province name="北京">
* <city>
* <name>海淀区</name>
* <description>haidianQu</description>
* </city>
* <city>
* <name>西土城区</name>
* <description>xituchengQu</description>
* </city>
* </province>
* <province name="安徽">
* <city>
* <name>合肥市</name>
* <description>hefei</description>
* </city>
* <city>
* <name>蚌埠市</name>
* <description>bengbu</description>
* </city>
* </province>
* </china>
*/
@Test
public void func4(){
//得到省份list
List<Province>provinceList=getProvince();
//创建XSTream对象
XStream xStream=new XStream();
//将生成的xml内容对应的标签替换别名
xStream.alias("china",List.class);
xStream.alias("province",Province.class);
xStream.alias("city",City.class);
//隐藏掉省份中的城市集合属性
xStream.addImplicitCollection(Province.class,"arrayList");
//把province类的成员，变成province标签的属性
xStream.useAttributeFor(Province.class,"name");
//得到省份对象的xml
String s=xStream.toXML(provinceList);
System.out.println(s);
}
/**
*
* 去掉city中的description
* <china>
* <province name="北京">
* <city>
* <name>海淀区</name>
* </city>
* <city>
* <name>西土城区</name>
* </city>
* </province>
* <province name="安徽">
* <city>
* <name>合肥市</name>
* </city>
* <city>
* <name>蚌埠市</name>
* </city>
* </province>
* </china>
*/
@Test
public void func5(){
//得到省份list
List<Province>provinceList=getProvince();
//创建XSTream对象
XStream xStream=new XStream();
//将生成的xml内容对应的标签替换别名
xStream.alias("china",List.class);
xStream.alias("province",Province.class);
xStream.alias("city",City.class);
//隐藏掉省份中的城市集合属性
xStream.addImplicitCollection(Province.class,"arrayList");
//把province类的成员，变成province标签的属性
xStream.useAttributeFor(Province.class,"name");
//去掉city中的description
xStream.omitField(City.class,"description");
//得到省份对象的xml
String s=xStream.toXML(provinceList);
System.out.println(s);
}
}