[学习交流] xStream完美转换XML ,json

xStream框架 xStream可以轻易的将Java对象和xml文档相互转换，而且可以修改某个特定的属性和节点名称，而且也支持json的转换；前面有介绍过json-lib这个框架，在线博文：http://www.cnblogs.com/hoojo/archive/2011/04/21/2023805.html以及Jackson这个框架，在线博文：http://www.cnblogs.com/hoojo/archive/2011/04/22/2024628.html它们都完美支持JSON，但是对xml的支持还不是很好。一定程度上限制了对Java对象的描述，不能让xml完全体现到对Java对象的描述。这里将会介绍xStream对JSON、XML的完美支持。xStream不仅对XML的转换非常友好，而且提供annotation注解，可以在JavaBean中完成对xml节点、属性的描述。以及对JSON也支持，只需要提供相关的JSONDriver就可以完成转换。一、准备工作 1、下载jar包、及官方资源 xStream的jar下载地址： http://download.csdn.net/detail/u013791374/9636008官方的示例很全，官方参考示例：http://xstream.codehaus.org/tutorial.html添加xstream-1.3.1.jar文件到工程中，就可以开始下面的工作；2、测试用例代码 import com.thoughtworks.xstream.XStream;

/**
 * @author zwj
 *
 * 2016-9-21下午3:09:53
 * XStream java转换xml
 */
public class XStreamTest {

 public static void main(String[] args) {
 System.out.println(setBean());

 }
 public static String setBean(){
 Student sdt = new Student();
 sdt.setId(1);
 sdt.setName("张无忌");
 sdt.setEmail("zhangwuji@sina.com");
 sdt.setAddress("www.baidu.com");
 return beanToXml(sdt);
 }

 public static String beanToXml(Student sdt){
 XStream xst = new XStream();
 xst.alias("xml", sdt.getClass());//设置别名
 return xst.toXML(sdt);//将对象转换成xml
 }
}
通过XStream对象的toXML方法就可以完成Java对象到XML的转换，toXML方法还有2个相同签名的方法，需要传递一个流。然后通过流来完成xml信息的输出。3、需要的JavaBean package com.hoo.entity; package com.cn.test.objecttoxml;

import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;

public class Student {
 private int id;

 private String name;

 private String email;

 private String address;

 public String toString() {
 return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE);
 }

 //getter、setter

}

运行后结果如下： ------------Bean->XML------------<xml>
<id>1</id>
<name>张无忌</name>
<email>zhangwuji@sina.com</email>
<address>皖六安</address>
< /xml> 2、将List集合转换成xml文档 /** * function:将Java的List集合转换成XML对象 * @author hoojo * @createDate Nov 27, 2010 12:20:07 PM */ public static void main(String[] args) { System.out.println(setBean()); } public static String setBean(){ List<Student> list = new ArrayList<Student>(); Student sd = new Student(); sd.setId(1); sd.setName("张无忌"); sd.setEmail("zhangwuji@sina.com"); sd.setAddress("皖六安"); list.add(sd); Student sd2 = new Student(); sd2.setId(1); sd2.setName("张无忌2"); sd2.setEmail("zhangwuji@sina.com2"); sd2.setAddress("皖六安2"); list.add(sd2); return beanToXml(list); } public static String beanToXml(Object obj){ XStream xst = new XStream(); //xstream list转xml 设置<list>标签别名 xstream.alias("xxx", List.class); xst.alias("xml",List.class); //aliasPackage 设置包别名 xst.aliasPackage("list", "com.cn.test.objecttoxml"); return xst.toXML(obj); } 上面的代码运行后，结果如下： ----------List-->XML----------<xml>
<list.Student>
 <id>1</id>
 <name>张无忌</name>
 <email>zhangwuji@sina.com</email>
 <address>皖六安</address>
</list.Student>
<list.Student>
 <id>1</id>
 <name>张无忌2</name>
 <email>zhangwuji@sina.com2</email>
 <address>皖六安2</address>
</list.Student>
< /xml> 如果不加xstream.addImplicitCollection(ListBean.class, "list"); 这个设置的话，会出现一个List节点包裹着Student节点元素。添加addImplicitCollection可以忽略这个list节点元素。那么上面的list节点就不存在，只会在beans元素中出现name、student这2个xml元素标签；setMode是设置相同的对象的引用方式，如果设置XStream.NO_REFERENCES就是不引用，会输出2分相同的Student元素。如果是XStream.ID_REFERENCES会引用相同的那个对象的id属性，如果是XStream.XPATH_ABSOLUTE_REFERENCES引用，那么它将显示xpath路径。上面采用的id引用，<student reference="3"/>这个引用了id=3的那个student标签元素；useAttributeFor是设置某个节点显示到父节点的属性中，也就是将指定class中的指定属性，在这个class元素节点的属性中显示。如：<student><name>hoojo</name></student> 设置好后就是这样的结果：<student name=”hoojo”></student> aliasAttribute是修改属性名称。
3、 Map集合转换xml文档 /** * function:Java Map集合转XML * @author hoojo * @createDate Nov 27, 2010 1:13:26 PM */@Testpublic void writeMap2XML() { try { Map<String,Student> map = new HashMap<String,Student>();
 Student sd = new Student();
 sd.setId(1);
 sd.setName("张无忌");
 sd.setEmail("zhangwuji@sina.com");
 sd.setAddress("皖六安");
 map.put("No.1", sd);

 Student sd2 = new Student();
 sd2.setId(2);
 sd2.setName("张无忌2");
 sd2.setEmail("zhangwuji@sina.com2");
 sd2.setAddress("皖六安2");
 map.put("No.2", sd2);
 return beanToXml(map) } catch (Exception e) { e.printStackTrace(); }}public static String beanToXml(Object obj){ XStream xst = new XStream(); //不需要设置MAP.CLASS //xst.alias("xml",Map.class); xst.alias("student", Student.class); xst.alias("key", String.class); xst.useAttributeFor(Student.class, "id"); //aliasPackage 设置包别名 return xst.toXML(obj); }运行后结果如下： ---------Map --> XML---------<map>
<entry>
 <key>No.1</key>
 <student id="1">
 <name>张无忌</name>
 <email>zhangwuji@sina.com</email>
 <address>皖六安</address>
 </student>
</entry>
<entry>
 <key>No.2</key>
 <student id="2">
 <name>张无忌2</name>
 <email>zhangwuji@sina.com2</email>
 <address>皖六安2</address>
 </student>
</entry>
< /map>

5、用OutStream输出流写XML /** * function:用OutStream输出流写XML * @author hoojo * @createDate Nov 27, 2010 1:13:48 PM */@Testpublic void writeXML4OutStream() { try { out = xstream.createObjectOutputStream(System.out); Student stu = new Student(); stu.setName("jack"); Classes c = new Classes("一班", bean, stu); c.setNumber(2); failRed("---------ObjectOutputStream # JavaObject--> XML---------"); out.writeObject(stu); out.writeObject(new Birthday("2010-05-33")); out.write(22);//byte out.writeBoolean(true); out.writeFloat(22.f); out.writeUTF("hello"); } catch (Exception e) { e.printStackTrace(); }}使用输出流后，可以通过流对象完成xml的构建，即使没有JavaBean对象，你可以用流来构建一个复杂的xml文档，运行后结果如下： ---------ObjectOutputStream # JavaObject--> XML---------<object-stream> <com.hoo.entity.Student> <id>0</id> <name>jack</name> </com.hoo.entity.Student> <com.hoo.entity.Birthday> <birthday>2010-05-33</birthday> </com.hoo.entity.Birthday> <byte>22</byte> <boolean>true</boolean> <float>22.0</float> <string>hello</string></object-stream>三、XML内容转换Java对象
1、将xml文档转换成Java对象 /** * function:将XML字符串转换成Java对象 * @author hoojo * @createDate Nov 27, 2010 2:39:06 PM */@Testpublic void readXml2Object() { try { Student sd = new Student(); sd.setId(1); sd.setName("张无忌"); sd.setEmail("zhangwuji@sina.com"); sd.setAddress("皖六安"); xst.alias("xml",obj.getClass()); String xmlStr = xst.toXML(obj); System.out.println("java对象转xml："+xmlStr); Student sdt = (Student)xst.fromXML(xmlStr); System.out.println("对象转换xml方法："+sdt.toString()); } catch (Exception e) { e.printStackTrace(); }}运行后结果如下： -----------Xml >>> Bean--------------java对象转xml：<xml> <id>1</id> <name>张无忌</name> <email>zhangwuji@sina.com</email> <address>皖六安</address></xml>对象转换xml方法：Student[id=1,name=张无忌,email=zhangwuji@sina.com,address=皖六安] 怎么样，成功的完成XML到JavaBean、List、Map的转换，更多对象转换还需要大家一一尝试。用法类似~这里就不一样赘述。四、XStream对JSON的支持 xStream对JSON也有非常好的支持，它提供了2个模型驱动。用这2个驱动可以完成Java对象到JSON的相互转换。使用JettisonMappedXmlDriver驱动，将Java对象转换成json，需要添加jettison.jar1、用JettisonMappedXmlDriver完成Java对象到JSON的转换 /** * function:XStream结合JettisonMappedXmlDriver驱动，转换Java对象到JSON * 需要添加jettison jar * @author hoojo * @createDate Nov 27, 2010 1:23:18 PM */@Testpublic void writeEntity2JETTSON() { failRed("=======JettisonMappedXmlDriver===JavaObject >>>> JaonString========="); xstream = new XStream(new JettisonMappedXmlDriver()); xstream.setMode(XStream.NO_REFERENCES); xstream.alias("student", Student.class); fail(xstream.toXML(bean));}运行后结果如下： =======JettisonMappedXmlDriver===JavaObject >>>> JaonString========={"student":{"id":1,"name":"jack","email":"jack@email.com","address":"china","birthday":[{},"2010-11-22"]}}JSON的转换和XML的转换用法一样，只是创建XStream需要传递一个参数，这个参数就是xml到JSON映射转换的驱动。这里会降到两个驱动，分别是JettisonMappedXmlDriver、JsonHierarchicalStreamDriver。2、 JsonHierarchicalStreamDriver完成Java对象到JSON的转换 /** * function:用XStream结合JsonHierarchicalStreamDriver驱动 * 转换java对象为JSON字符串 * @author hoojo * @createDate Nov 27, 2010 1:16:46 PM */@Testpublic void writeEntiry2JSON() { failRed("======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString========="); xstream = new XStream(new JsonHierarchicalStreamDriver()); //xstream.setMode(XStream.NO_REFERENCES); xstream.alias("student", Student.class); failRed("-------Object >>>> JSON---------"); fail(xstream.toXML(bean)); //failRed("========JsonHierarchicalStreamDriver==删除根节点========="); //删除根节点 xstream = new XStream(new JsonHierarchicalStreamDriver() { public HierarchicalStreamWriter createWriter(Writer out) { return new JsonWriter(out, JsonWriter.DROP_ROOT_MODE); } }); //xstream.setMode(XStream.NO_REFERENCES); xstream.alias("student", Student.class); fail(xstream.toXML(bean));}运行后结果如下： ======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========-------Object >>>> JSON---------{"student": { "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" }}}{ "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" }}使用JsonHierarchicalStreamDriver转换默认会给转换后的对象添加一个根节点，但是在构建JsonHierarchicalStreamDriver驱动的时候，你可以重写createWriter方法，删掉根节点。看上面的结果，一个是默认带根节点的JSON对象，它只是将类名作为一个属性，将对象作为该属性的一个值。而另一个没有带根属性的JSON就是通过重写createWriter方法完成的。3、将List集合转换成JSON字符串 @Testpublic void writeList2JSON() { failRed("======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString========="); JsonHierarchicalStreamDriver driver = new JsonHierarchicalStreamDriver(); xstream = new XStream(driver); //xstream = new XStream(new JettisonMappedXmlDriver());//转换错误 //xstream.setMode(XStream.NO_REFERENCES); xstream.alias("student", Student.class); List<Student> list = new ArrayList<Student>(); list.add(bean);//add bean = new Student(); bean.setAddress("china"); bean.setEmail("tom@125.com"); bean.setId(2); bean.setName("tom"); Birthday day = new Birthday("2010-11-22"); bean.setBirthday(day); list.add(bean);//add bean = new Student(); bean.setName("jack"); list.add(bean);//add fail(xstream.toXML(list)); //failRed("========JsonHierarchicalStreamDriver==删除根节点========="); //删除根节点 xstream = new XStream(new JsonHierarchicalStreamDriver() { public HierarchicalStreamWriter createWriter(Writer out) { return new JsonWriter(out, JsonWriter.DROP_ROOT_MODE); } }); xstream.alias("student", Student.class); fail(xstream.toXML(list));}运行后结果如下 ======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========##{"list": [ { "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" } }, { "id": 2, "name": "tom", "email": "tom@125.com", "address": "china", "birthday": { "birthday": "2010-11-22" } }, { "id": 0, "name": "jack" }]}#[ { "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" } }, { "id": 2, "name": "tom", "email": "tom@125.com", "address": "china", "birthday": { "birthday": "2010-11-22" } }, { "id": 0, "name": "jack" }]上面的list1是使用JsonHierarchicalStreamDriver 转换的，当然你也可以使用JettisonMappedXmlDriver驱动进行转换；用JettisonMappedXmlDriver转换后，你会发现格式不同而且没有根属性。4、 Map转换json @Testpublic void writeMap2JSON() { failRed("======JsonHierarchicalStreamDriver==== Map >>>> JaonString========="); xstream = new XStream(new JsonHierarchicalStreamDriver()); //xstream = new XStream(new JettisonMappedXmlDriver()); xstream.alias("student", Student.class); Map<String, Student> map = new HashMap<String, Student>(); map.put("No.1", bean);//put bean = new Student(); bean.setAddress("china"); bean.setEmail("tom@125.com"); bean.setId(2); bean.setName("tom"); bean.setBirthday(new Birthday("2010-11-21")); map.put("No.2", bean);//put bean = new Student(); bean.setName("jack"); map.put("No.3", bean);//put fail(xstream.toXML(map)); //failRed("========JsonHierarchicalStreamDriver==删除根节点========="); //删除根节点 xstream = new XStream(new JsonHierarchicalStreamDriver() { public HierarchicalStreamWriter createWriter(Writer out) { return new JsonWriter(out, JsonWriter.DROP_ROOT_MODE); } }); xstream.alias("student", Student.class); fail(xstream.toXML(map));}运行后结果如下： ======JsonHierarchicalStreamDriver==== Map >>>> JaonString========={"map": [ [ "No.3", { "id": 0, "name": "jack" } ], [ "No.1", { "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" } } ], [ "No.2", { "id": 2, "name": "tom", "email": "tom@125.com", "address": "china", "birthday": { "birthday": "2010-11-21" } } ]]}[ [ "No.3", { "id": 0, "name": "jack" } ], [ "No.1", { "id": 1, "name": "jack", "email": "jack@email.com", "address": "china", "birthday": { "birthday": "2010-11-22" } } ], [ "No.2", { "id": 2, "name": "tom", "email": "tom@125.com", "address": "china", "birthday": { "birthday": "2010-11-21" } } ]]5、将JSON转换java对象 /** * function:JsonHierarchicalStreamDriver可以将简单的json字符串转换成java对象，list、map转换不成功； * JsonHierarchicalStreamDriver读取JSON字符串到java对象出错 * @author hoojo * @createDate Nov 27, 2010 1:22:26 PM * @throws JSONException */@Testpublic void readJSON2Object() throws JSONException { String json = "{\"student\": {" + "\"id\": 1," + "\"name\": \"haha\"," + "\"email\": \"email\"," + "\"address\": \"address\"," + "\"birthday\": {" + "\"birthday\": \"2010-11-22\"" + "}" + "}}"; //JsonHierarchicalStreamDriver读取JSON字符串到java对象出错，但JettisonMappedXmlDriver可以 xstream = new XStream(new JettisonMappedXmlDriver()); xstream.alias("student", Student.class); fail(xstream.fromXML(json).toString()); //JettisonMappedXmlDriver转换List集合出错，但JsonHierarchicalStreamDriver可以转换正确 //JettisonMappedXmlDriver 转换的字符串 {"list":{"student":[{"id":1,"name":"haha","email":"email","address":"address","birthday":[{},"2010-11-22"]}]},"student":{"id":2,"name":"tom","email":"tom@125.com","address":"china","birthday":[{},"2010-11-22"]}} json = "{\"list\": [{" + "\"id\": 1," + "\"name\": \"haha\"," + "\"email\": \"email\"," + "\"address\": \"address\"," + "\"birthday\": {" + "\"birthday\": \"2010-11-22\"" + "}" + "},{" + "\"id\": 2," + "\"name\": \"tom\"," + "\"email\": \"tom@125.com\"," + "\"address\": \"china\"," + "\"birthday\": {" + "\"birthday\": \"2010-11-22\"" + "}" + "}]}"; System.out.println(json);//用js转换成功 List list = (List) xstream.fromXML(json); System.out.println(list.size());//0好像转换失败}运行后结果如下： haha#1#address#2010-11-22#email{"list": [{"id": 1,"name": "haha","email": "email","address": "address","birthday": {"birthday": "2010-11-22"}},{"id": 2,"name": "tom","email": "tom@125.com","address": "china","birthday": {"birthday": "2010-11-22"}}]}0JSON到Java的转换是fromXML方法。

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[学习交流] xStream完美转换XML ,json

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