XStream使用详解

先来一个小例子：

public class Demo {

    /**
     * xml json javabean之间的相互转换
     */
    @Test
    public void beanToXml() {
        
        /**
         * DomDriver()
         * StaxDriver()
         */
        XStream xstream = new XStream();//需要xpp3的jar文件
//        XStream xstream = new XStream(new DomDriver());
//        XStream xstream = new XStream(new StaxDriver()); //不换行，适合网络传输
        
        
        /**
         * javaBean to xml
         */
        Person p = new Person(1, "略略", false, new Date(), Arrays.asList(new String[] {"打球", "游戏", "动漫"}));
        //类重命名，去除包名，以下两种都可
//        xstream.alias("Person", Person.class);
//        xstream.aliasPackage("", "entity");
        //类重命名，修改包名
//        xstream.alias("xxx.Person", Person.class);
//        xstream.aliasPackage("xxx", "entity");
        //为字段重命名
//        xstream.aliasField("性别", Person.class, "gender");
        //把字段设置成属性
//        xstream.useAttributeFor(Person.class, "id");
        //隐藏字段
//        xstream.omitField(Person.class, "hobby");
        
        String xml = xstream.toXML(p);
        System.out.println(xml);
        
        /**
         * beanList to xml
         */
        Person[] ps = { new Person(1, "略略", false, new Date(), Arrays.asList(new String[] {"打球", "游戏", "动漫"})),
                new Person(2, "哈哈", false, new Date(), Arrays.asList(new String[] {"打球"}))
            };
        //忽略集合根节点
        
        List<Person> list = Arrays.asList(ps);
        xml = xstream.toXML(list);
        System.out.println(xml);
        
        
        /**
         * 使用注解
         */
        
    }
    
    /**
     * xml转换成javabean
     */
    @Test
    public void xmlToBean() {
        
        XStream xstream = new XStream(new DomDriver());
        
        String xml = "<?xml version=\"1.0\" ?><entity.Person><id>1</id><name>略略</name><gender>false</gender><birthday>2017-04-15 02:16:34.664 UTC</birthday><hobby class=\"java.util.Arrays$ArrayList\"><a class=\"string-array\"><string>打球</string><string>游戏</string><string>动漫</string></a></hobby></entity.Person>";
        Person person = (Person) xstream.fromXML(xml);
        System.out.println(person);
        
        xml = "<?xml version=\"1.0\" ?><java.util.Arrays_-ArrayList><a class=\"entity.Person-array\"><entity.Person><id>1</id><name>略略</name><gender>false</gender><birthday>2017-04-15 02:18:26.457 UTC</birthday><hobby class=\"java.util.Arrays$ArrayList\"><a class=\"string-array\"><string>打球</string><string>游戏</string><string>动漫</string></a></hobby></entity.Person><entity.Person><id>2</id><name>哈哈</name><gender>false</gender><birthday>2017-04-15 02:18:26.457 UTC</birthday><hobby class=\"java.util.Arrays$ArrayList\"><a class=\"string-array\"><string>打球</string></a></hobby></entity.Person></a></java.util.Arrays_-ArrayList>";
        List<Person> plist = (List<Person>) xstream.fromXML(xml);
        System.out.println(plist);
    }
    
    /**
     * java to json
     */
    @Test
    public void beanToJson() {
        
        XStream xStream = new XStream(new JettisonMappedXmlDriver());
        
        Person p = new Person(1, "略略", false, new Date(), Arrays.asList(new String[] {"打球", "游戏", "动漫"}));
        String json = xStream.toXML(p);
        System.out.println(json);
        
        json = "{\"entity.Person\":{\"id\":1,\"name\":\"略略\",\"gender\":false,\"birthday\":\"2017-04-15 02:38:41.767 UTC\",\"hobby\":{\"@class\":\"java.util.Arrays$ArrayList\",\"a\":{\"@class\":\"string-array\",\"string\":[\"打球\",\"游戏\",\"动漫\"]}}}}";
        Person t = (Person) xStream.fromXML(json);
        System.out.println(t);
    }
    
}

 

 

XStream使用详解

转载：http://www.cnblogs.com/LiZhiW/p/4313493.html#_label1

阅读目录

• 开始
• 1.Xstream介绍
• 2.Xstream的基本使用
• 3.Xstream序列化重命名
• 4.Xstream注解的使用
• 5.Xstream自定义的转换器
• 6.Xstream对象流的使用
• 7.Xstream持久化API
• 8.Xstream操作Json

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1.Xstream介绍

(1)Xstream介绍

    Xstream是一种OXMapping 技术，是用来处理XML文件序列化的框架,在将JavaBean序列化，或将XML文件反序列化的时候，不需要其它辅助类和映射文件，使得XML序列化不再繁索。Xstream也可以将JavaBean序列化成Json或反序列化，使用非常方便。

(2)Xstream的简单例子

1. class Person//JavaBean实体类
2. {
3. private String name;
4. private int age;
5. public Person(String name,int age)
6. {
7. this.name=name;
8. this.age=age;
9. }
10. @Override
11. public String toString()
12. {
13. return "Person [name=" + name + ", age=" + age + "]";
14. }
15. }
16. public class Test
17. {
18. public static void main(String[] args)
19. {
20. Person bean=new Person("张三",19);
21. XStream xstream = new XStream();
22. //XML序列化
23. String xml = xstream.toXML(bean);
24. System.out.println(xml);
25. //XML反序列化
26. bean=(Person)xstream.fromXML(xml);
27. System.out.println(bean);
29. xstream = new XStream(new JettisonMappedXmlDriver());
30. xstream.setMode(XStream.NO_REFERENCES);
31. //Json序列化
32. String json=xstream.toXML(bean);
33. System.out.println(json);
34. //Json反序列
35. bean=(Person)xstream.fromXML(json);
36. System.out.println(bean);
37. }
38. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. </test.Person>
5. Person [name=张三, age=19]
6. {"test.Person":{"name":"张三","age":19}}
7. Person [name=张三, age=19

    注意：Xstream序列化XML时需要引用的jar包：xstream-[version].jar、xpp3-[version].jar、xmlpull-[version].jar。Xstream序列化Json需要引用的jar包：jettison-[version].jar。

    使用Xstream序列化时，对JavaBean没有任何限制。JavaBean的字段可以是私有的，也可以没有getter或setter方法，还可以没有默认的构造函数。

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2.Xstream的基本使用

(1)Xstream序列化XML

    Xstream序列化XML时可以允许用户使用不同的XML解析器，用户可以使用一个标准的JAXP DOM解析器或自Java6集成StAX解析器。这样用户就不需要依赖xpp3-[version].jar。

    Xstream序列化XML时，也可以对XML节点重命名。

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean=new Person("张三",19);
6. //XStream xstream = new XStream();//需要XPP3库
7. //XStream xstream = new XStream(new DomDriver());//不需要XPP3库
8. XStream xstream = new XStream(new StaxDriver());//不需要XPP3库开始使用Java6
9. xstream.alias("人",Person.class);//为类名节点重命名
10. //XML序列化
11. String xml = xstream.toXML(bean);
12. System.out.println(xml);
13. //XML反序列化
14. bean=(Person)xstream.fromXML(xml);
15. System.out.println(bean);
16. }
17. }

    程序运行结果：

1. <?xml version="1.0" ?><人><name>张三</name><age>19</age></人>
2. Person [name=张三, age=19]

(2)Xstream序列化Json

    Xstream序列化Json与序列化XML类似，例如：

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean=new Person("张三",19);
6. XStream xstream = new XStream(new JettisonMappedXmlDriver());//设置Json解析器
7. xstream.setMode(XStream.NO_REFERENCES);//设置reference模型,不引用
8. xstream.alias("人",Person.class);//为类名节点重命名
9. //Json序列化
10. String xml = xstream.toXML(bean);
11. System.out.println(xml);
12. //Json反序列化
13. bean=(Person)xstream.fromXML(xml);
14. System.out.println(bean);
15. }
16. }

    程序运行结果：

1. {"人":{"name":"张三","age":19}}
2. Person [name=张三, age=19]

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3.Xstream序列化重命名

(1)为包重命名：Xstream.aliasPackage()方法

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean=new Person("张三",19);
6. XStream xstream = new XStream();
7. xstream.aliasPackage("com.lzw", "test");//为包名称重命名
8. //序列化
9. String xml = xstream.toXML(bean);
10. System.out.println(xml);
11. //反序列化
12. bean=(Person)xstream.fromXML(xml);
13. System.out.println(bean);
14. }
15. }

    程序运行结果：

1. <com.lzw.Person>
2. <name>张三</name>
3. <age>19</age>
4. </com.lzw.Person>
5. Person [name=张三, age=19]

(2)为类重命名：Xstream.alias()方法

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean=new Person("张三",19);
6. XStream xstream = new XStream();
7. xstream.alias("人", Person.class);//为类名节点重命名
8. //序列化
9. String xml = xstream.toXML(bean);
10. System.out.println(xml);
11. //反序列化
12. bean=(Person)xstream.fromXML(xml);
13. System.out.println(bean);
14. }
15. }

    程序运行结果：

1. <人>
2. <name>张三</name>
3. <age>19</age>
4. </人>
5. Person [name=张三, age=19]

(3)为字段重命名：Xstream.aliasField()方法

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean=new Person("张三",19);
6. XStream xstream = new XStream();
7. xstream.aliasField("姓名", Person.class,"name");//为类的字段节点重命名
8. xstream.aliasField("年龄", Person.class,"age");//为类的字段节点重命名
9. //序列化
10. String xml = xstream.toXML(bean);
11. System.out.println(xml);
12. //反序列化
13. bean=(Person)xstream.fromXML(xml);
14. System.out.println(bean);
15. }
16. }

    程序运行结果：

1. <test.Person>
2. <姓名>张三</姓名>
3. <年龄>19</年龄>
4. </test.Person>
5. Person [name=张三, age=19]

(4)省略集合根节点：Xstream.addImplicitCollection()方法

1. class Person
2. {
3. private String name;
4. private int age;
5. private List friends;
6. public Person(String name, int age, String... friends)
7. {
8. this.name = name;
9. this.age = age;
10. this.friends = Arrays.asList(friends);
11. }
12. @Override
13. public String toString()
14. {
15. return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
16. }
17. }
18. public class Test
19. {
20. public static void main(String[] args)
21. {
22. Person bean =new Person("张三",19,"李四","王五","赵六");
23. XStream xstream = new XStream();
24. xstream.addImplicitCollection(Person.class, "friends");//省略集合根节点
25. //序列化
26. String xml = xstream.toXML(bean);
27. System.out.println(xml);
28. //反序列化
29. bean=(Person)xstream.fromXML(xml);
30. System.out.println(bean);
31. }
32. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. <string>李四</string>
5. <string>王五</string>
6. <string>赵六</string>
7. </test.Person>
8. Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(5)把字段节点设置成属性：Xstream.useAttributeFor()方法

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean =new Person("张三",19,"李四","王五","赵六");
6. XStream xstream = new XStream();
7. xstream.useAttributeFor(Person.class, "name");//把字段节点设置成属性
8. //序列化
9. String xml = xstream.toXML(bean);
10. System.out.println(xml);
11. //反序列化
12. bean=(Person)xstream.fromXML(xml);
13. System.out.println(bean);
14. }
15. }

    程序运行结果：

1. <test.Person name="张三">
2. <age>19</age>
3. <friends class="java.util.Arrays$ArrayList">
4. <a class="string-array">
5. <string>李四</string>
6. <string>王五</string>
7. <string>赵六</string>
8. </a>
9. </friends>
10. </test.Person>
11. Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(6)隐藏字段：xstream.omitField()方法

1. public class Test
2. {
3. public static void main(String[] args)
4. {
5. Person bean =new Person("张三",19,"李四","王五","赵六");
6. XStream xstream = new XStream();
7. xstream.omitField(Person.class, "friends");//把字段节点隐藏
8. //序列化
9. String xml = xstream.toXML(bean);
10. System.out.println(xml);
11. //反序列化
12. bean=(Person)xstream.fromXML(xml);
13. System.out.println(bean);
14. }
15. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. </test.Person>
5. Person [name=张三, age=19, friends=null]

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4.Xstream注解的使用

(1)设置Xstream应用注解

    使用Xstream注解前需要对Xstream进行配置，可以使用两种方式：应用某个JavaBean类的注解或自动使用JavaBean类的注解。代码如下：

1. XStream xstream = new XStream();
2. xstream.processAnnotations(Person.class);//应用Person类的注解
3. xstream.autodetectAnnotations(true);//自动检测注解

(2)重命名注解：@XStreamAlias()

1. @XStreamAlias("人")
2. class Person
3. {
4. @XStreamAlias("姓名")
5. private String name;
6. @XStreamAlias("年龄")
7. private int age;
8. @XStreamAlias("朋友")
9. private List friends;
10. public Person(String name, int age, String... friends)
11. {
12. this.name = name;
13. this.age = age;
14. this.friends = Arrays.asList(friends);
15. }
16. @Override
17. public String toString()
18. {
19. return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
20. }
21. }

    程序运行结果：

1. <人>
2. <姓名>张三</姓名>
3. <年龄>19</年龄>
4. <朋友 class="java.util.Arrays$ArrayList">
5. <a class="string-array">
6. <string>李四</string>
7. <string>王五</string>
8. <string>赵六</string>
9. </a>
10. </朋友>
11. </人>
12. Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(3)省略集合根节点：@XStreamImplicit

1. class Person
2. {
3. private String name;
4. private int age;
5. //@XStreamImplicit//只隐藏集合根节点
6. @XStreamImplicit(itemFieldName="朋友")//设置重复的节点名，可能会导致无法反序列化
7. private List<String> friends;
8. public Person(String name, int age, String... friends)
9. {
10. this.name = name;
11. this.age = age;
12. this.friends = Arrays.asList(friends);
13. }
14. @Override
15. public String toString()
16. {
17. return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
18. }
19. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. <朋友>李四</朋友>
5. <朋友>王五</朋友>
6. <朋友>赵六</朋友>
7. </test.Person>
8. Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(4)把字段节点设置成属性：@XStreamAsAttribute

1. class Person
2. {
3. @XStreamAsAttribute
4. private String name;
5. @XStreamAsAttribute
6. private int age;
7. private List<String> friends;
8. public Person(String name, int age, String... friends)
9. {
10. this.name = name;
11. this.age = age;
12. this.friends = Arrays.asList(friends);
13. }
14. @Override
15. public String toString()
16. {
17. return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
18. }
19. }

    程序运行结果：

1. <test.Person name="张三" age="19">
2. <friends class="java.util.Arrays$ArrayList">
3. <a class="string-array">
4. <string>李四</string>
5. <string>王五</string>
6. <string>赵六</string>
7. </a>
8. </friends>
9. </test.Person>
10. Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(5)隐藏字段：@XStreamOmitField

1. class Person
2. {
3. private String name;
4. private int age;
5. @XStreamOmitField
6. private List<String> friends;
7. public Person(String name, int age, String... friends)
8. {
9. this.name = name;
10. this.age = age;
11. this.friends = Arrays.asList(friends);
12. }
13. @Override
14. public String toString()
15. {
16. return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
17. }
18. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. </test.Person>
5. Person [name=张三, age=19, friends=null]

(6)设置转换器：@XStreamConverter()

1. class Person
2. {
3. private String name;
4. private int age;
5. @XStreamConverter(value=BooleanConverter.class,booleans={false},strings={"男","女"})
6. private boolean sex;
7. public Person(String name, int age, boolean sex)
8. {
9. this.name = name;
10. this.age = age;
11. this.sex=sex;
12. }
13. @Override
14. public String toString()
15. {
16. return "Person [name=" + name + ", age=" + age + ", sex=" + sex + "]";
17. }
18. }

    程序运行结果：

1. <test.Person>
2. <name>张三</name>
3. <age>19</age>
4. <sex>男</sex>
5. </test.Person>
6. Person [name=张三, age=19, sex=true]

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5.Xstream自定义的转换器

(1)Xstream自带的转换器

    Xstream内部有许多转换器，用于JavaBean对象到XML或Json之间的转换。这些转换器的详细信息网址：http://xstream.codehaus.org/converters.html

(2)使用自定义的转换器

1. class Person
2. {
3. private String name;
4. private int age;
5. public Person(String name, int age)
6. {
7. this.name = name;
8. this.age = age;
9. }
10. public String getName()
11. {
12. return name;
13. }
14. public void setName(String name)
15. {
16. this.name = name;
17. }
18. public int getAge()
19. {
20. return age;
21. }
22. public void setAge(int age)
23. {
24. this.age = age;
25. }
26. @Override
27. public String toString()
28. {
29. return "Person [name=" + name + ", age=" + age + "]";
30. }
31. }
32. public class PersonConverter implements Converter
33. {
34. @Override//定义转换器能转换的JavaBean类型
35. public boolean canConvert(Class type)
36. {
37. return type.equals(Person.class);
38. }
39. @Override//把对象序列化成XML或Json
40. public void marshal(Object value, HierarchicalStreamWriter writer,
41. MarshallingContext context)
42. {
43. Person person = (Person) value;
44. writer.startNode("姓名");
45. writer.setValue(person.getName());
46. writer.endNode();
47. writer.startNode("年龄");
48. writer.setValue(person.getAge()+"");
49. writer.endNode();
50. writer.startNode("转换器");
51. writer.setValue("自定义的转换器");
52. writer.endNode();
53. }
54. @Override//把XML或Json反序列化成对象
55. public Object unmarshal(HierarchicalStreamReader reader,
56. UnmarshallingContext context)
57. {
58. Person person = new Person("",-1);
59. reader.moveDown();
60. person.setName(reader.getValue());
61. reader.moveUp();
62. reader.moveDown();
63. person.setAge(Integer.parseInt(reader.getValue()));
64. reader.moveUp();
65. return person;
66. }
67. }
68. public class Test
69. {
70. public static void main(String[] args)
71. {
72. Person bean =new Person("张三",19);
73. XStream xstream = new XStream();
74. xstream.registerConverter(new PersonConverter());//注册转换器
75. //序列化
76. String xml = xstream.toXML(bean);
77. System.out.println(xml);
78. //反序列化
79. bean=(Person)xstream.fromXML(xml);
80. System.out.println(bean);
81. }
82. }

    程序运行结果：

1. <test.Person>
2. <姓名>张三</姓名>
3. <年龄>19</年龄>
4. <转换器>自定义的转换器</转换器>
5. </test.Person>
6. Person [name=张三, age=19]

(3)常用的转换器接口与抽象类

    SingleValueConverter：单值转换接口

    AbstractSingleValueConverter：单值转换抽象类

    Converter：常规转换器接口

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6.Xstream对象流的使用

(1)Xstream对象输出流

1. class Person
2. {
3. private String name;
4. private int age;
5. public Person(String name, int age)
6. {
7. this.name = name;
8. this.age = age;
9. }
10. }
11. public class Test
12. {
13. public static void main(String[] args) throws IOException
14. {
15. XStream xstream = new XStream();
16. ObjectOutputStream out = xstream.createObjectOutputStream(System.out);
17. out.writeObject(new Person("张三",12));
18. out.writeObject(new Person("李四",19));
19. out.writeObject("Hello");
20. out.writeInt(12345);
21. out.close();
22. }
23. }

    程序运行结果：

1. <object-stream>
2. <test.Person>
3. <name>张三</name>
4. <age>12</age>
5. </test.Person>
6. <test.Person>
7. <name>李四</name>
8. <age>19</age>
9. </test.Person>
10. <string>Hello</string>
11. <int>12345</int>
12. </object-stream>

    注意：XStream对象流是通过标准java.io.ObjectOutputStream和java.io.ObjectInputStream对象。因为XML文档只能有一个根节点,必须包装在一个序列化的所有元素 额外的根节点。 这个根节点默认 < object-stream > 上面的例子所示。 

(2)Xstream对象输出流

1. class Person
2. {
3. private String name;
4. private int age;
5. public Person(String name, int age)
6. {
7. this.name = name;
8. this.age = age;
9. }
10. @Override
11. public String toString()
12. {
13. return "Person [name=" + name + ", age=" + age + "]";
14. }
15. }
16. public class Test
17. {
18. public static void main(String[] args) throws IOException, ClassNotFoundException
19. {
20. String s="<object-stream><test.Person><name>张三</name><age>12</age></test.Person><int>12345</int></object-stream>";
21. StringReader reader = new StringReader(s);
22. XStream xstream = new XStream();
23. ObjectInputStream in = xstream.createObjectInputStream(reader);
24. System.out.println((Person) in.readObject());
25. System.out.println(in.readInt());
26. }
27. }

    程序运行结果：

1. Person [name=张三, age=12]
2. 12345

回到顶部

7.Xstream持久化API

(1)保存JavaBean对象

1. class Person
2. {
3. private String name;
4. private int age;
5. public Person(String name, int age)
6. {
7. this.name = name;
8. this.age = age;
9. }
10. @Override
11. public String toString()
12. {
13. return "Person [name=" + name + ", age=" + age + "]";
14. }
15. }
16. public class Test
17. {
18. public static void main(String[] args) throws IOException, ClassNotFoundException
19. {
20. PersistenceStrategy strategy = new FilePersistenceStrategy(new File("D:\\tmp"));
21. List list = new XmlArrayList(strategy);
22. list.add(new Person("张三",13));//保存数据
23. list.add(new Person("李四",21));
24. list.add(new Person("王五",17));
25. }
26. }

    程序运行结果：如果我们检查D:\tmp目录,有三个文件:int@0.xml、int@1.xml、int@2.xml；每个对象都被序列化到XML文件里。

(2)读取并删除JavaBean对象

1. public class Test
2. {
3. public static void main(String[] args) throws IOException, ClassNotFoundException
4. {
5. PersistenceStrategy strategy = new FilePersistenceStrategy(new File("D:\\tmp"));
6. List list = new XmlArrayList(strategy);
7. for (Iterator it = list.iterator(); it.hasNext();)
8. {
9. System.out.println((Person) it.next());
10. it.remove();//删除对象序列化文件
11. }
12. }
13. }

    程序运行结果：

1. Person [name=张三, age=13]
2. Person [name=李四, age=21]
3. Person [name=王五, age=17]

回到顶部

8.Xstream操作Json

(1)Xstream序列化Json的重命名

1. @XStreamAlias("人")
2. class Person
3. {
4. @XStreamAlias("姓名")
5. private String name;
6. @XStreamAlias("年龄")
7. private int age;
8. public Person(String name, int age)
9. {
10. this.name = name;
11. this.age = age;
12. }
13. @Override
14. public String toString()
15. {
16. return "Person [name=" + name + ", age=" + age + "]";
17. }
18. }
19. public class Test
20. {
21. public static void main(String[] args)
22. {
23. Person bean=new Person("张三",19);
24. XStream xstream = new XStream(new JettisonMappedXmlDriver());//设置Json解析器
25. xstream.autodetectAnnotations(true);
26. //Json序列化
27. String xml = xstream.toXML(bean);
28. System.out.println(xml);
29. //Json反序列化
30. bean=(Person)xstream.fromXML(xml);
31. System.out.println(bean);
32. }
33. }

    程序运行结果：

1. {"人":{"姓名":"张三","年龄":19}}
2. Person [name=张三, age=19]

    注意：Xstream序列化Json的重命名的方式与其序列化成XML的方式一样！

(2)去掉序列化Json的根节点

1. class Person
2. {
3. private String name;
4. private int age;
5. public Person(String name, int age)
6. {
7. this.name = name;
8. this.age = age;
9. }
10. @Override
11. public String toString()
12. {
13. return "Person [name=" + name + ", age=" + age + "]";
14. }
15. }
16. public class Test00
17. {
18. public static void main(String[] args)
19. {
20. Person bean=new Person("张三",19);
21. XStream xstream = new XStream(new JsonHierarchicalStreamDriver()
22. {
23. public HierarchicalStreamWriter createWriter(Writer writer)
24. {
25. return new JsonWriter(writer, JsonWriter.DROP_ROOT_MODE);
26. }
27. });
28. //Json序列化
29. String xml = xstream.toXML(bean);
30. System.out.println(xml);
31. }
32. }

    程序运行结果：

1. { "name": "张三", "age": 19 }

    注意：去掉根节点后的Json串是不能反序列化的，因为XStream 不知道它的类型。

(3)Json的解析器区别

    前面两个例子使用了不同的Json解析器，这里说明他们的不同之处：

1. JettisonMappedXmlDriver：是支持序列化和反序列化Json的。
2. JsonHierarchicalStreamDriver：只支持序列化，不支持反序列化。

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