引言
随着工作時間的推移，參加過的面試也是挺多的。記錄下參與面試中的一些經典代碼閱讀題。
對象與Map
Map取值測試:
package net.xqlee.project.demo;
public class Person {
public Person(String name) {
this.name = name;
}
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package net.xqlee.project.demo;
import java.util.HashMap;
import java.util.Map;
public class DemoMap {
public static void main(String[] args) {
Map map = new HashMap<>();
map.put(new Person("leftso"), "leftso");
map.put(new Person("小左"), "小左");
String personName = map.get(new Person("leftso"));
System.out.println(personName);
}
}
控制台列印結果(提示:滑鼠選中空白區域檢視答案):
null
while循環
package net.xqlee.project.demo;
public class DemoWhile {
public static void main(String[] args) {
int y = 7;
int x = 4;
while ((x += 2) < y) {
do {
System.out.print(x + " ");
} while (++y < 9);
}
}
}
控制台輸出結果(提示:滑鼠選中空白區域檢視答案):
6 6 8
整數Integer
package net.xqlee.project.demo;
public class DemoInteger {
public static void main(String[] args) {
Integer a = 20, b = 20, c = 150, d = 150;
int a1 = 20, b1 = 20, c1 = 150, d1 = 150;
System.out.print((a == b) + " " + (c == d) + " " + (a1 == b1) + " " + (c1 == d1));
}
}
控制台輸出:
true false true true
集合List
package net.xqlee.project.demo;
import java.util.ArrayList;
import java.util.List;
public class DemoList {
public static void main(String[] args) {
List list=new ArrayList<>();
list.add(new Integer(20));
list.add(new Integer(30));
list.add(new Float(2.2));
for (Integer integer : list) {
System.out.print(integer+" ");
}
}
}
控制台輸出:
編譯時錯誤
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