DecimalFormat(숫자 형식 클래스)

 

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
//추상클래스는 new를 사용할 수 없다!!!!!!
	//자식클래스나 메소드를 이용해야 한다.
	public static void main(String[] args) {
		NumberFormat nf = new DecimalFormat();
		//아무것도 안해도 3자리마다 ,찍고 소수이하 3째자리
		System.out.println(nf.format(12345678.456789));
		System.out.println(nf.format(12345678));
		System.out.println();
        }
 }

12,345,678.457 12,345,678

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {
		
		NumberFormat nf2 = new DecimalFormat("#,###.##원");
		//소수점 이하의 숫자가 유효숫자가 아닌것은 표현하지 않는다
		System.out.println(nf2.format(12345678.456789));
		System.out.println(nf2.format(12345678));
		System.out.println();
        }
}

12,345,678.46원 12,345,678원

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {
		
		NumberFormat nf3 = new DecimalFormat("#,###.00원");
		//0을 강제로 표시
		System.out.println(nf3.format(12345678.456789));
		System.out.println(nf3.format(12345678));
		System.out.println();
        
        }
}

12,345,678.46원 12,345,678.00원

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {

		NumberFormat nf4 = NumberFormat.getInstance();
		nf4.setMaximumFractionDigits(2); //소수이하2쨰자리
		nf4.setMinimumFractionDigits(2); //강제로 0이표시
		System.out.println(nf4.format(12345678.456789));
		System.out.println(nf4.format(12345678));
		System.out.println();
        }
}
        

12,345,678.46 12,345,678.00

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {

		//NumberFormat nf5 = NumberFormat.getInstance(Locale.US);
		//NumberFormat nf5 = NumberFormat.getCurrencyInstance(Locale.US);//달러표시
		NumberFormat nf5 = NumberFormat.getCurrencyInstance(Locale.JAPAN);//엔화표시
		nf5.setMaximumFractionDigits(2); //소수이하2쨰자리
		nf5.setMinimumFractionDigits(2); //강제로 0이표시
		System.out.println(nf5.format(12345678.456789));
		System.out.println(nf5.format(12345678));
		System.out.println();
        }
}

￥12,345,678.46 ￥12,345,678.00

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {
	
		NumberFormat nf6 = new DecimalFormat("-#.0원");
		//0을 강제로 표시
		System.out.println(nf6.format(123.45));
		System.out.println(nf6.format(1234));
		System.out.println();
        }
   }

-123.5원 -1234.0원

---

package abstracrMethod_0929;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberTest {
	public static void main(String[] args) {

		NumberFormat nf7 = new DecimalFormat("+#.0원");
		//0을 강제로 표시
		System.out.println(nf7.format(123.45));
		System.out.println(nf7.format(1234));
		System.out.println();
	}
}

+123.5원 +1234.0원