[ Java ] ArrayList Sort 소트 정렬 샘플

Java ArrayList 소트 샘플

  ArrayList<String> nameList = new ArrayList<String>();

  nameList.add("AAA");
  nameList.add("BBB");
  nameList.add("CCC");
  Collections.sort(nameList);

[ Java ] Calender 날짜 비교

중략

날짜 비교 before , after , equals

Calendar c1 = Calendar.getInstance();
Calendar c2 = Calendar.getInstance();
c1.set(2013, 4, 1);
c2.set(2013, 4, 1);

if (c1.before(c2))
{
 System.out.print(" is before ");
}
if (c1.after(c2))
{
 System.out.print(" is after ");
}
if (c1.equals(c2))
{
 System.out.print("same ");
}

[ Java ] split . 에러

String test="aaa.bbb.ccc";

test.split(".");

에러난다.

아래처럼 하믄 된다.
test.split("\\.");

[ Java ] Calendar format String

Calendar startDay = Calendar.getInstance();

SimpleDateFormat sdf
    = new SimpleDateFormat ("yyyy.MM.dd");

String start = sdf.format(startDay.getTime());

[ Jsp ][ Java ] 메일 전송

메일 보내기

package Common;

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;

import org.apache.log4j.Logger;

public class chkMailSender{
static Logger drLog = Logger.getLogger("dr");
// Member Function
        // 제목, 본문
public void sendMail(String title, String body){
String to = "to@xxxx.com";
String from = "from@xxxx.com";
String host = "mail.xxxx.com";
String id = "id@xxxx.com";
String pwd = "password";

Properties props = new Properties();
props.put("mail.smtp.host", host);

Session sess = Session.getDefaultInstance(props, null);

try {
Message msg = new MimeMessage(sess);
msg.setFrom(new InternetAddress(from));
InternetAddress[] address = { new InternetAddress(to) };
msg.setRecipients(Message.RecipientType.TO, address);
msg.setSubject(title);
msg.setSentDate(new Date());
msg.setContent(body, "text/html; charset=UTF-8");

Transport transport = sess.getTransport("smtp");
transport.connect(host, id, pwd);
transport.sendMessage(msg, msg.getAllRecipients());
transport.close();

} catch (MessagingException mex) {
drLog.equals(mex.getMessage());
}
}
}

[ Jsp ][ Java ] 이번 달 마지막 날짜 오늘 날짜 비교

오늘이 이번 달 마지막 날이면 //해야할 처리

GregorianCalendar today = new GregorianCalendar ( );
int maxday = today.getActualMaximum ( ( today.DAY_OF_MONTH ) );
drLog.info(maxday);

int todayDay = today.get(today.DAY_OF_MONTH);
drLog.info(todayDay);

if(maxday == todayDay){
//해야할 처리
}

[ Jsp ][ Java ] 객체 (클래스) 파일 읽기 쓰기

객체 쓰기

쓸객체는 implements Serializable를 해야한다
예) public class chkChargeList implements Serializable   {};

chkChargeList list = new chkChargeList();
FileOutputStream outFile = new FileOutputStream(filename);
ObjectOutputStream outStream = new ObjectOutputStream( outFile );
outStream.writeObject (list);

객체 읽기
FileInputStream inFile = new FileInputStream (filename);
ObjectInputStream inStream = new ObjectInputStream (inFile);
chkChargeList test = (chkChargeList) inStream.readObject();
system.out.println(test.getBasicCharge());

[ Jsp ][ Java ] static final long 선언

아래와 같이 하니깐 eclipse에서 에러 메세지가 난다.
private static final long sizeUnit = 53687091200;

뒤에 L을 붙여주면 된다
private static final long sizeUnit = 53687091200L;

[ jsp ][ java ] 폴더 사이즈 계산

파일패스 넣어주면 폴더 사이즈를 돌려준다.

package Common;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.channels.FileChannel;

public class chkFolderSize{
// Member Variables
private long dFolderSize;
private long NG=-1;
// Constructor
public chkFolderSize() {
dFolderSize = 0;
}
//calculate folder size
private void calcSize(File tFolder){
File[] fList = tFolder.listFiles();
for(int i=0; i < fList.length; i++){
if(fList[i].isFile()){
dFolderSize += fList[i].length();
}else{
calcSize(fList[i]);
}
}
}
// return folder size
public long getFolderSize(String fPath){
long retVal;
File tFolder = new File(fPath);
if(tFolder.exists()&&tFolder.isDirectory()){
calcSize(tFolder);
retVal = dFolderSize;
}else{
retVal = NG;
}
return retVal;
}

}

[ jsp ][ java ] 이미지 회전

90도 회전 시키기 샘플, 화질이 조금 떨어 지는 듯

BufferedImage oldImage = ImageIO.read(new FileInputStream(oldFile));

BufferedImage newImage = new                                   BufferedImage(oldImage.getHeight(),oldImage.getWidth(), oldImage.getType());

Graphics2D graphics = (Graphics2D) newImage.getGraphics();

graphics.rotate(Math.toRadians(90), newImage.getWidth() / 2, newImage.getHeight() / 2);

graphics.translate((newImage.getWidth() - oldImage.getWidth()) / 2, (newImage.getHeight() - oldImage.getHeight()) / 2);

graphics.drawImage(oldImage, 0, 0, oldImage.getWidth(), oldImage.getHeight(), null);

ImageIO.write(newImage, "JPG", new FileOutputStream(newFile));