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: https://nexus.codehaus.org/content/repositories/releases/com/thoughtworks/xstream/xstream-distribution/1.3.1/xstream-distribution-1.3.1-bin.zip 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;需要的jar如下:
2、 测试用例代码 package com.hoo.test;
import java.io.IOException; import java.io.ObjectInputStream;
import java.io.ObjectOutputStream; import java.io.StringReader; import java.io.Writer; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; import org.codehaus.jettison.json.JSONException; import org.junit.After; import org.junit.Before; import org.junit.Test; import com.hoo.entity.Birthday; import com.hoo.entity.Classes; import com.hoo.entity.ListBean; import com.hoo.entity.Student; import com.thoughtworks.xstream.XStream; import com.thoughtworks.xstream.io.HierarchicalStreamWriter; import com.thoughtworks.xstream.io.json.JettisonMappedXmlDriver; import com.thoughtworks.xstream.io.json.JsonHierarchicalStreamDriver; import com.thoughtworks.xstream.io.json.JsonWriter; /** * <b>function:</b>Java对象和XML字符串的相互转换 * jar-lib-version: xstream-1.3.1 * @author hoojo * @createDate Nov 27,2010 12:15:15 PM * @file XStreamTest.java * @package com.hoo.test * @project WebHttpUtils * @blog http://blog.csdn.net/IBM_hoojo * @email hoojo_@126.com * @version 1.0 */ @SuppressWarnings("unchecked")
public class XStreamTest {
private XStream xstream = null;
private ObjectOutputStream out = null;
private ObjectInputStream in = null; private Student bean = null; * <b>function:</b>初始化资源准备 * @author hoojo * @createDate Nov 27,2010 12:16:28 PM */ @Before void init() { try {
xstream = new XStream();
//xstream = new XStream(new DomDriver()); // 需要xpp3 jar
} catch (Exception e) {
e.printStackTrace(); } bean = new Student();
bean.setAddress("china");
bean.setEmail("jack@email.com");
bean.setId(1); bean.setName("jack");
Birthday day = new Birthday();
day.setBirthday("2010-11-22");
bean.setBirthday(day); } * <b>function:</b>释放对象资源 @After void destory() { xstream = null; bean = null; if (out != null) {
out.flush(); out.close(); } if (in != null) { in.close(); } catch (IOException e) { System.gc(); } final void fail(String string) {
System.out.println(string); void failRed(String string) { System.err.println(string); } 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;
class Student { private int id;
private String name; private String email; private String address; private Birthday birthday; //getter、setter public String toString() { return this.name + "#" + this.id + this.address + this.birthday + this.email; }
二、Java转换成XML 1、 JavaBean转换XM * <b>function:</b>Java对象转换成XML字符串
@Test void writeBean2XML() { fail("------------Bean->XML------------");
fail(xstream.toXML(bean)); "重命名后的XML"); //类重命名 //xstream.alias("account",Student.class); //xstream.alias("生日",Birthday.class); //xstream.aliasField("生日",Student.class,"birthday"); //fail(xstream.toXML(bean)); //属性重命名 xstream.aliasField("邮件",Student.class,"email"); //包重命名 xstream.aliasPackage("hoo",128)">"com.hoo.entity");
} e.printStackTrace();
} 看结果中的第一份xml内容,是没有经过然后修改或重命名的文档,按照原样输出。文档中的第二份文档的package经过重命名,email属性也经过重命名以及类名也可以进行重命名的。 运行后结果如下: ------------Bean->XML------------
<com.hoo.entity.Student> <id>1</id <name>jack</name<email>jack@email.com</email<address>china</<birthday>2010-11-22</birthday</com重命名后的XML <hoo<邮件</邮件</hoo> 2、 将List集合转换成xml文档 * <b>function:</b>将Java的List集合转换成XML对象
void writeList2XML() { //修改元素名称 xstream.alias("beans",ListBean.class); xstream.alias("student",244)"> fail("----------List-->XML----------"); ListBean listBean = new ListBean();
listBean.setName("this is a List Collection");
List<Object> list = new ArrayList<Object>();
list.add(bean); list.add(bean);//引用bean
//list.add(listBean);//引用listBean,父元素 bean = bean.setAddress( bean.setEmail("tom@125.com");
bean.setId(2); bean.setName("tom");
Birthday day = new Birthday( listBean.setList(list); //将ListBean中的集合设置空元素,即不显示集合元素标签 //xstream.addImplicitCollection(ListBean.class,"list"); //设置reference模型 //xstream.setMode(XStream.NO_REFERENCES);//不引用 xstream.setMode(XStream.ID_REFERENCES);//id引用
//xstream.setMode(XStream.XPATH_ABSOLUTE_REFERENCES);//绝对路径引用 //将name设置为父类(Student)的元素的属性 xstream.useAttributeFor(Student."name");
xstream.useAttributeFor(Birthday."birthday");
//修改属性的name xstream.aliasAttribute("姓名",128)">"生日",Birthday. fail(xstream.toXML(listBean)); } e.printStackTrace();
} 上面的代码运行后,结果如下: ----------List-->XML----------
<beans id="1">this is a List Collection<list id="2"<student id="3" 姓名="jack" <birthday id="4" 生日="2010-11-22"/</student<student reference="3"/<student id="5" 姓名="tom">2>tom@125<birthday id="6" 生日="2010-11-22"/</list</beans> 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、 在JavaBean中添加Annotation注解进行重命名设置 先看看JavaBean的代码 import java.util.Arrays;
import java.util.Calendar; import java.util.GregorianCalendar; import com.thoughtworks.xstream.annotations.XStreamAlias; import com.thoughtworks.xstream.annotations.XStreamAsAttribute; import com.thoughtworks.xstream.annotations.XStreamConverter; import com.thoughtworks.xstream.annotations.XStreamImplicit; import com.thoughtworks.xstream.annotations.XStreamOmitField; @XStreamAlias("class")
class Classes { /* * 设置属性显示 @XStreamAsAttribute @XStreamAlias("名称")
* 忽略 @XStreamOmitField int number; @XStreamImplicit(itemFieldName = "Students")
private List<Student> students; @SuppressWarnings("unused")
@XStreamConverter(SingleValueCalendarConverter.class)
private Calendar created = new GregorianCalendar();
public Classes(){} public Classes(String name,Student... stu) { this.name = name; this.students = Arrays.asList(stu); } SingleValueCalendarConverter.java这个是一个类型转换器 import java.util.Date;
import com.thoughtworks.xstream.converters.Converter; import com.thoughtworks.xstream.converters.MarshallingContext; import com.thoughtworks.xstream.converters.UnmarshallingContext; import com.thoughtworks.xstream.io.HierarchicalStreamReader; class SingleValueCalendarConverter implements Converter {
void marshal(Object source,HierarchicalStreamWriter writer,
MarshallingContext context) { Calendar calendar = (Calendar) source; writer.setValue(String.valueOf(calendar.getTime().getTime())); public Object unmarshal(HierarchicalStreamReader reader,244)"> UnmarshallingContext context) { GregorianCalendar calendar = calendar.setTime(new Date(Long.parseLong(reader.getValue())));
return calendar;
} @SuppressWarnings(boolean canConvert(Class type) {
return type.equals(GregorianCalendar.}
再看看测试用例代码 @Test
void writeList2XML4Annotation() { failRed("---------annotation Bean --> XML---------");
Student stu = stu.setName( Classes c = new Classes("一班",bean,stu);
c.setNumber(2); //对指定的类使用Annotation //xstream.processAnnotations(Classes.class); //启用Annotation //xstream.autodetectAnnotations(true); fail(xstream.toXML(c)); } 当启用annotation或是对某个特定的类启用annotation时,上面的classes这个类才有效果。如果不启用annotation,运行后结果如下: ---------annotation Bean --> XML---------
.Classes>一班<number</number<students class="java.util.Arrays$ArrayList"<a class="student-array"<student >0</a</students<created<time>1303292056718</time<timezone>Asia/Shanghai</timezone</created> 当启用annotation后xstream.processAnnotations(Classes.class),结果如下: <class 名称="一班"<Students</Students>1303292242937</class>
4、 Map集合转换xml文档 * <b>function:</b>Java Map集合转XML
void writeMap2XML() { failRed("---------Map --> XML---------");
Map<String,Student> map = new HashMap<String,Student>();
map.put("No.1",bean);//put map.put("No.2",128)">"No.3",128)">"key",String. xstream.useAttributeFor(Student."id"); xstream.useAttributeFor("birthday",244)"> fail(xstream.toXML(map));
} 运行后结果如下: ---------Map --map<entry<key>No.3</key<student id="0"</entry>No.1<student id="1"<birthday birthday="2010-11-22"/>No.2<student id="2">tom>
5、 用OutStream输出流写XML * <b>function:</b>用OutStream输出流写XML
void writeXML4OutStream() { out = xstream.createObjectOutputStream(System.out); Student stu = stu.setName( Classes c = c.setNumber(2);
"---------ObjectOutputStream # JavaObject--> XML---------"); out.writeObject(stu); out.writeObject("2010-05-33"));
out.write(22);//byte
out.writeBoolean(true); out.writeFloat(22.f); out.writeUTF("hello");
} 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--object-stream.Birthday>2010-05-33<byte>22</byte<boolean>true</booleanfloat>22.0<string>hello</string>
三、XML内容转换Java对象 1、 用InputStream将XML文档转换成java对象 * <b>function:</b>用InputStream将XML文档转换成java对象
* 需要额外的jar xpp3-main.jar void readXML4InputStream() { String s = "<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>"; "---------ObjectInputStream## XML --> javaObject---------"); StringReader reader = new StringReader(s);
in = xstream.createObjectInputStream(reader); Student stu = (Student) in.readObject(); Birthday b = (Birthday) in.readObject(); byte i = in.readByte(); boolean bo = in.readBoolean(); float f = in.readFloat(); String str = in.readUTF(); System.out.println(stu); System.out.println(b); System.out.println(i); System.out.println(bo); System.out.println(f); System.out.println(str); } 读取后,转换的Java对象,结果如下: ---------ObjectInputStream## XML --> javaObject---------
jack#0#null#null#null 2010-05-33 22 true 22.0 hello 2、 将xml文档转换成Java对象 * <b>function:</b>将XML字符串转换成Java对象
void readXml2Object() { "-----------Xml >>> Bean--------------"); Student stu = (Student) xstream.fromXML(xstream.toXML(bean)); fail(stu.toString()); List<Student> list = new ArrayList<Student>();
//add list.add(bean);"==========XML >>> List===========");
List<Student> studetns = (List<Student>) xstream.fromXML(xstream.toXML(list)); "size:" + studetns.size());//3
for (Student s : studetns) { fail(s.toString()); "==========XML >>> Map==========="); "size:" + maps.size()); Set<String> key = maps.keySet();
Iterator<String> iter = key.iterator(); while (iter.hasNext()) { String k = iter.next(); fail(k + ":" + map.get(k));
} 运行后结果如下: -----------Xml >>> Bean--------------
jack#1#china#2010-11-22#jack@email.com ==========XML >>> List=========== size:3 jack#1#china#2010-11-22#jack@email.com tom#2#china#2010-11-22#tom@125.com jack#0#null#null#null ==========XML >>> Map=========== size:3 No.3:jack#0#null#null#null No.1:jack#1#china#2010-11-22#jack@email.com No.2:tom#2#china#2010-11-22#tom@125.com 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.jar 1、 用JettisonMappedXmlDriver完成Java对象到JSON的转换 * <b>function:</b>XStream结合JettisonMappedXmlDriver驱动,转换Java对象到JSON
* 需要添加jettison jar void writeEntity2JETTSON() { failRed("=======JettisonMappedXmlDriver===JavaObject >>>> JaonString=========");
xstream = new XStream(new JettisonMappedXmlDriver()); xstream.setMode(XStream.NO_REFERENCES); xstream.alias( fail(xstream.toXML(bean));
=======JettisonMappedXmlDriver===JavaObject >>>> JaonString========= {"student":{"id":1,128)">"name":"jack",128)">"email":"jack@email.com",128)">"address":"china",128)">"birthday":[{},128)">"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 * <b>function:</b>用XStream结合JsonHierarchicalStreamDriver驱动
* 转换java对象为JSON字符串 void writeEntiry2JSON() { "======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString========="); new JsonHierarchicalStreamDriver()); //xstream.setMode(XStream.NO_REFERENCES); "-------Object >>>> JSON---------"); fail(xstream.toXML(bean)); //failRed("========JsonHierarchicalStreamDriver==删除根节点========="); //删除根节点 new JsonHierarchicalStreamDriver() { public HierarchicalStreamWriter createWriter(Writer out) { new JsonWriter(out,JsonWriter.DROP_ROOT_MODE); }); ======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString========= -------Object >>>> JSON--------- {"student": {
"id": 1,128)">"name": "email": "address": "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 void writeList2JSON() {
JsonHierarchicalStreamDriver driver = new JsonHierarchicalStreamDriver();
xstream = new XStream(driver);
//xstream = new XStream(new JettisonMappedXmlDriver());//转换错误 List<Student> list = list.add(bean); bean = bean.setAddress( bean.setEmail( bean.setId(2);
bean.setName( Birthday day = bean.setBirthday(day);
list.add(bean); bean = fail(xstream.toXML(list));
xstream.alias(}
运行后结果如下 ##{"list": [
{ },244)"> { "id": 2,128)">"tom",128)">"tom@125.com",244)"> },128)">"id": 0,128)">"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 void writeMap2JSON() {
"======JsonHierarchicalStreamDriver==== Map >>>> JaonString========="); //xstream = new XStream(new JettisonMappedXmlDriver()); Map<String,monospace; font-size:10pt; direction:ltr; background-color:white"> map.put( bean.setBirthday("2010-11-21"));
bean.setName( fail(xstream.toXML(map));
}); ======JsonHierarchicalStreamDriver==== Map >>>> JaonString========= "map": [ [ { ],244)"> [ { } "2010-11-21" ] ]} [ ],244)"> } ] ] 5、 将JSON转换java对象 * <b>function:</b>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 * @throws JSONException void readJSON2Object() throws JSONException {
String json = "{"student": {" +
""id": 1," + ""name": "haha",128)">""email": "email",128)">""address": "address",128)">""birthday": {" + ""birthday": "2010-11-22"" + "}" + "}}"; //JsonHierarchicalStreamDriver读取JSON字符串到java对象出错,但JettisonMappedXmlDriver可以 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","2010-11-22"]}} json = "{"list": [{" +
"},{" +
""id": 2,128)">""name": "tom",128)">""email": "tom@125.com",128)">""address": "china",128)">"}]}"; 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
haha#1#address#2010-11-22#email "list": [{"haha",128)">"email",128)">"address",128)">"birthday": {"2010-11-22"}},128)">"2010-11-22"}}]} 0 JSON到Java的转换是fromXML方法。 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |