Object 클래스
class Student {
int id;
String name;
Student(int id, String name) {
this.id = id;
this.name = name;
}
@Override
public String toString() {
return id + ":" + name;
}
}
public class Main {
public static void main(String[] args) {
Student student = new Student(20214609, "hyeonsu");
System.out.println(student);//20214609:hyeonsu 출력
}
}
class Student {
int id;
String name;
Student(int id, String name) {
this.id = id;
this.name = name;
}
@Override
public String toString() {
return id + ":" + name;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof Student) {
Student std = (Student) obj;
if (std.id == this.id) return true;
else return false;
}
return false;
}
}
public class Main {
public static void main(String[] args) {
Student student = new Student(20214609, "hyeonsu");
Student student2 = new Student(20214609, "hyeonsu");
System.out.println(student);
System.out.println(student.equals(student2));
}
}
String 클래스
String str1 = new String("abc");
String str2 = "test";
public class Main {
public static void main(String[] args) {
String javaStr = new String("java");
String androidStr = new String("android");
javaStr = javaStr.concat(androidStr);
System.out.println(javaStr);
}
}
public class Main {
public static void main(String[] args) {
String javaStr = new String("java");
StringBuilder buffer = new StringBuilder(javaStr);
buffer.append(" and");
buffer.append(" android");
buffer.append(" programming is fun!");
System.out.println(buffer);
}
}
Wrapper 클래스
Integer iValue = new Integer(100);
int myValue = iValue.intValue();//int 값 가져오기
Integer number1 = Integer.valueOf("100");
Integer number2 = Interger.valueOf(100);
int num = Integer.parseInt("100");//문자열이 어떤 숫자를 나타낼 때 문자열을 int로 반환할 수 있다.