[자바] StringBuilder, StringBuffer 사용법

StringBuffer

append

public class Test {
    public static void main(String[] args) {
        StringBuffer sb = new StringBuffer();
        sb.append("안녕);
        sb.append(" ");
        sb.append("난 kyu!");
        System.out.println(sb.toString());
    }
}

안녕 난 kyu!

insert

public class Test {
    public static void main(String[] args) {
        StringBuffer sb = new StringBuffer();
        sb.append("난 kyu!");
        sb.insert(0, "안녕 ");
        System.out.println(sb.toString());
    }
}

안녕 난 kyu!

substring

public class Test {
    public static void main(String[] args) {
        StringBuffer sb = new StringBuffer();
        sb.append("안녕 난 kyu!");
        System.out.println(sb.substring(0, 4));
    }
}

안녕  난

StringBuilder

StringBuffer와 사용법이 같음

String VS StringBuilder VS StringBuffer

	String	StringBuilder	StringBuffer
보관	String pool	Heap	Heap
성능	Fast	Fast	Slow
스레드 세이프	YES	NOPE	YES
Syncronized	YES	NOPE	YES
Modifiable	Immutable	Mutable	Mutable