今天恰好聽一位長輩訴說XML的一些優點，可交換性、檔案小等，於是乎就上java tutorial看了簡單的範例，順便把目前在手上處理的資料拿來練習，有JAXB API進行java<->xml真的不難，宣告JAXBContext(主要的處理mapping抽象類別)並傳入欲轉換的POJO類別，要進行java-to-xml則是使用Marshaller類別，建立實例後呼叫marshal並傳入pojo以及outputstream，XML就產生了，相反的，進行xml-to-java則是使用Unmarshaller類別，或許這是簡單的例子，更進階JAXB annotations應用可以參考官方API，以下是今天自己練習的code。

參考網址:http://docs.oracle.com/javase/tutorial/jaxb/intro/index.html
XMLProcess
Main

package xml;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.Iterator;
import java.util.List;

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

import read.GetDataFromFile;

import alarm.Alarm;

public class XMLProcess {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
			Path path=Paths.get("L:\\alarm.xml");//取得檔案路徑
			OutputStream out=Files.newOutputStream(path, StandardOpenOption.WRITE);//建立output物件 
			JAXBContext alcon;//主要處理java/xml mapping的抽象類別
			try{
				alcon=JAXBContext.newInstance(Alarm.class);//建立Alarm連結，另外要注意Alarm類別要加註@XMLRootElement， 
				                                                                                         //否則會拋出找不到rootelement例外
				Marshaller m = alcon.createMarshaller();//從java object轉換到xml是使用Marshaller類別
																									//反向則是用Unmarshaller
				GetDataFromFile gf=new GetDataFromFile();
				List<Alarm> aplist=gf.readFromExcel();//一大堆Alarm物件
				Iterator<Alarm> it=aplist.iterator();
				while(it.hasNext()){
					m.marshal(it.next(), out);//將物件轉換成XML格事後寫入檔案
				}
				}catch (Exception e){
					e.printStackTrace();
				}
				
			}
			
	}

POJO

package alarm;

import javax.xml.bind.annotation.XmlRootElement;


@XmlRootElement
public class Alarm {
	private String refid;
	private String alarmid;
	private String des;
	private String state;
	private String sys;
	
	public String getRefid() {
		return refid;
	}
	public void setRefid(String refid) {
		this.refid = refid;
	}
	public String getAlarmid() {
		return alarmid;
	}
	public void setAlarmid(String alarmid) {
		this.alarmid = alarmid;
	}
	public String getDes() {
		return des;
	}
	public void setDes(String des) {
		this.des = des;
	}
	public String getState() {
		return state;
	}
	public void setState(String state) {
		this.state = state;
	}
	public String getSys() {
		return sys;
	}
	public void setSys(String sys) {
		this.sys = sys;
	}
}

output:(沒有特別format，是很ugly)

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><alarm><alarmid>A0G42:LT0001_SA.PNT</alarmid><des>SKIMMER SURGE TANK TNK-0001B LVL</des><refid>0G421003A003</refid><state></state><sys>0G42</sys></alarm><?xml version="1.0" encoding="UTF-8" standalone="yes"?><alarm><alarmid>A0G42:LT0001_SA.HIABS</alarmid><des>SKIMMER SURGE TANK TNK-0001B LVL</des><refid>0G421003A003</refid><state>HI HI</state><sys>0G42</sys></alarm><?xml version="1.0" encoding="UTF-8" standalone="yes"?><alarm><alarmid>A0G42:LT0001_SA.LOABS</alarmid><des>SKIMMER SURGE TANK TNK-0001B LVL</des><refid>0G421003A003</refid><state>LOW</state><sys>0G42</sys></alarm><?xml version="1.0" encoding="UTF-8" standalone="yes"?><alarm><alarmid>A0G42:LT0001_SA.LLOABS</alarmid><des>SKIMMER SURGE TANK TNK-0001B LVL</des><refid>0G421003A003</refid><state>LOW LOW</state><sys>0G42</sys></alarm><?xml version="1.0" encoding="UTF-8" standalone="yes"?><alarm><alarmid>A0G42:LT0010_SA.PNT</alarmid><des>AFPC POOL LEVEL</des><refid>0G421003A013</refid><state></state><sys>0G42</sys></alarm>