JAVA24. 类型判断
描述
父类Base有两个子类：Sub1、Sub2，现有一个方法getClassName()，要求传入Base类型的实例，在方法内部判定其具体的类型，返回的是类型的简单名字（不含包名），请补全getClassName()方法的判断逻辑。输入描述
输入要实例化的类名：Base、Sub1、Sub2 三者之一。输出描述
返回实例的实际类名（简化类名，不包含包的名字）。示例1
输入:
Sub1
输出:
Sub1
示例2
输入:
Sub2
输出:
Sub2
示例3
输入:
Base
输出:
Base
Java 解法, 执行用时: 14ms, 内存消耗: 9512KB, 提交时间: 2022-05-20
import java.util.Scanner;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String className = br.readLine();
Base obj = (Base) Class.forName(className).newInstance();
System.out.println(getClassName(obj));
}
public static String getClassName(Base obj) {
return obj.getClass().getName();
}
}
class Base {
}
class Sub1 extends Base {
}
class Sub2 extends Base {
}
Java 解法, 执行用时: 21ms, 内存消耗: 10656KB, 提交时间: 2022-04-27
import java.util.Scanner;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String className = br.readLine();
Base obj = (Base) Class.forName(className).newInstance();
System.out.println(getClassName(obj));
}
public static String getClassName(Base obj) {
// return obj.toString().split("@")[0];
return obj.getClass().getName();
}
}
class Base {
}
class Sub1 extends Base {
}
class Sub2 extends Base {
}
Java 解法, 执行用时: 24ms, 内存消耗: 10656KB, 提交时间: 2022-02-09
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
String className = scanner.next();
Base obj = (Base) Class.forName(className).newInstance();
System.out.println(getClassName(obj));
}
}
public static String getClassName(Base obj) {
if(obj instanceof Sub1){
return "Sub1";
}else if(obj instanceof Sub2){
return "Sub2";
}else{
return "Base";
}
}
}
class Base {
}
class Sub1 extends Base {
}
class Sub2 extends Base {
}
Java 解法, 执行用时: 25ms, 内存消耗: 10480KB, 提交时间: 2022-02-09
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
String className = scanner.next();
Base obj = (Base) Class.forName(className).newInstance();
System.out.println(getClassName(obj));
}
}
public static String getClassName(Base obj) {
if(obj instanceof Sub1){
return "Sub1";
}else if(obj instanceof Sub2){
return "Sub2";
}else{
return "Base";
}
//write your code here......
}
}
class Base {
}
class Sub1 extends Base {
}
class Sub2 extends Base {
}
Java 解法, 执行用时: 27ms, 内存消耗: 10504KB, 提交时间: 2021-10-17
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
String className = scanner.next();
Base obj = (Base) Class.forName(className).newInstance();
System.out.println(getClassName(obj));
}
}
public static String getClassName(Base obj) {
return obj.getClass().getName();
}
}
class Base {
}
class Sub1 extends Base {
}
class Sub2 extends Base {
}