使用JAXB完成XML与java对象的转换

SAX             处理超大xml时使用
dom4j           通过xpath来解析非常方便，适合处理较小的xml
Xstream--->Stax 基于流的方式处理
Xstream,Jackson 可以将json与java进行转换
JAXB java表中API，专门负责java与xml的互转
java--->xml:marshaller
xml--->java:unmarshaller


JAVB完成对象与XML的互转

package com.hqh.jaxb;

public class Classroom {
	private int id;
	private String name;
	private int grad;
	public Classroom() {
		super();
	}
	public Classroom(int id, String name, int grad) {
		super();
		this.id = id;
		this.name = name;
		this.grad = grad;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getGrad() {
		return grad;
	}
	public void setGrad(int grad) {
		this.grad = grad;
	}
	
	
}

package com.hqh.jaxb;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Student {
	private int id;
	private String name;
	private int age;
	private String sex;
	private Classroom classroom;
	
	public Student() {
		super();
	}

	public Student(int id, String name, int age, String sex, Classroom classroom) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.sex = sex;
		this.classroom = classroom;
	}

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}

	public Classroom getClassroom() {
		return classroom;
	}

	public void setClassroom(Classroom classroom) {
		this.classroom = classroom;
	}
	
	
}

package com.hqh.jaxb;


import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.junit.Test;

public class JAXBTest {
	
	/**Object--->XML*/
	@Test
	public void testMarshaller() throws Exception {
		//对象
		//要使用JAXB转换对象为xml，需要在对应的类上使用@XmlRootElement进行标注
		Classroom classroom = new Classroom(1, "一班", 2013);
		Student jaxbElement = new Student(1, "张三", 22, "男", classroom);
		
		//将student对象转为xml
		JAXBContext ctx = JAXBContext.newInstance(Student.class);
		Marshaller marshaller = ctx.createMarshaller();
		
		//将转换后的xml作为标准打印流输出
		marshaller.marshal(jaxbElement, System.out);
		
		//将转换后的xml以文件形式输出
		File file = new File("src/student.xml");
		if(!file.exists()) {
			file.createNewFile();
		}
		marshaller.marshal(jaxbElement, new FileOutputStream(file, false));
	}

	/**XML--->Object*/
	@Test
	public void testUnMarshaller() throws Exception {
		//XML
		InputStream is = this.getClass().getClassLoader().getResourceAsStream("student.xml");
		
		//将student对象转为xml转为student对象
		JAXBContext ctx = JAXBContext.newInstance(Student.class);
		Unmarshaller unmarshaller = ctx.createUnmarshaller();
		Object obj = unmarshaller.unmarshal(is);
		Student stu = (Student)obj;
		System.out.println(stu.getName()+","+stu.getClassroom().getName());
	}
}

将Student对象转换为xml的结果，很方便
如果存在中文转换，将项目的编码设置为UTF-8，不然中文为乱码

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<student>
	<age>22</age>
	<classroom>
		<grad>2013</grad>
		<id>1</id>
		<name>一班</name>
	</classroom>
	<id>1</id>
	<name>张三</name>
	<sex>男</sex>
</student>