第三题 有如下Student 对象, private String name; private int age; private int score; private String classNum; 其中,classNum 表示学生的班号,例如“class05”. 有如下List List list = new ArrayList(); list.add(new Student(“Tom”, 18, 100, “class05”)); list.add(new Student(“Jerry”,

需求:  计算一个字符串中每个字符出现的次数 思路: 通过toCharArray()拿到一个字符数组--> 遍历数组,将数组元素作为key,数值1作为value存入map容器--> 如果key重复,通过getKey()拿到value,计算value+1后存入 代码如下: import java.util.*; public class MapDemo { public static void main(String[] args) { String str = "sdnasjhdas

package Dec2016; public class Ques1207 { public static void main(String[] args) { new Test(); new Test(1); new Test("1"); System.out.println("实例数量为:"+Test.getNumOfInstances()); } } class Test{ private static int numOfInstances = 0; //

20161130问题解析请点击今日问题下方的"[Java每日一题]20161201"查看 package Dec2016; public class Ques1201 { public static void main(String[] args) { new Ques1201().sum(1, 2); } public void sum(int num1, int num2){ int temp = num1 + num2; System.out.println("没使用变

20170105问题解析请点击今日问题下方的"[Java每日一题]20170106"查看(问题解析在公众号首发,公众号ID:weknow619) package Jan2017; public class Ques0106 { public void method01(String... strings, int num){ } public void method02(String... strings, int... is){ } } 今日问题: 以上两个方法使用了变长参数,请问这

20170104问题解析请点击今日问题下方的"[Java每日一题]20170105"查看(问题解析在公众号首发,公众号ID:weknow619) package Jan2017; import java.util.ArrayList; import java.util.List; public class Ques0105 { public static void main(String[] args) { List<String> list = new ArrayList

20170103问题解析请点击今日问题下方的"[Java每日一题]20170104"查看(问题解析在公众号首发,公众号ID:weknow619) package Jan2017; import java.util.HashSet; import java.util.Set; public class Ques0104{ public static void main(String[] args){ Obj obj01 = new Obj("张三"); Obj obj

20161230问题解析请点击今日问题下方的"[Java每日一题]20170103"查看(问题解析在公众号首发,公众号ID:weknow619) package Jan2017; public class Ques0103 { public static void main(String[] args){ System.out.println(delete("你好", "你").equals("好")); System.out

// 20161229问题解析请点击今日问题下方的"[Java每日一题]20161230"查看(问题解析在公众号首发,公众号ID:weknow619)package Dec2016; public class Ques1230 { int array = {1, 2, 3}; // 1 int array[] = {1, 2, 3}; // 2 int[] array = {1, 2, 3}; // 3 int array[] = new int{1, 2, 3}; // 4 int

package Dec2016; import java.util.ArrayList; import java.util.List; public class Ques1229 { public static void main(String[] args){ Student stu01 = new Student("001"); Student stu02 = new Student(null); List<Student> students = new ArrayLi

package Dec2016; import java.util.ArrayList; import java.util.List; public class Ques1228 { public static void main(String[] arg){ Student stu01 = new Student("001"); Student stu02 = new Student("001 "); // stu02中001后面有个空格 List<Stud

package Dec2016; public class Ques1227 { public static void main(String[] args){ } { c = 1; } int c = 2; int a = b; int b = 3; } 今日问题: 请问主程序输出结果是什么?(点击以下"[Java每日一题]20161227"查看20161226问题解析) 题目原发布于公众号.简书:[Java每日一题]20161227,[Java每日一题]20161227 注:wek

package Dec2016; public class Ques1226 { static{ num = 1; } public static int num = 2; public static void main(String[] args) { System.out.println(num); } } 今日问题: 请问主程序输出结果是什么?(点击以下"[Java每日一题]20161226"查看20161223问题解析) 题目原发布于公众号.简书:[Java每日一题]20161

package Dec2016; public class Ques1223 { public static void main(String[] args){ Integer obj = Integer.valueOf(args[args.length - 1]); int i = obj.intValue(); if (args.length > 1) { System.out.println(i); } if (args.length > 0) { System.out.println(

package Dec2016; import java.util.Random; public class Ques1222 { public static void main(String[] args){ System.out.println("输出常量:"+Test.NUM); } } interface Test{ public static final float NUM = new Random().nextFloat(); } 今日问题: 请问主程序输出的值是不变的吗?

package Dec2016; public class Ques1221 { } class Parent{ public void test(){ System.out.println("Parent test"); } } class Sub extends Parent{ public String test(){ System.out.println("Sub test"); } } 今日问题: 请问主程序是否有编译错误?(点击以下"[Java

package Dec2016; public class Ques1220 { public static void main(String[] args) { Integer num1 = new Integer(100); Integer num2 = new Integer(100); compare(num1, num2); } public static void compare(Integer a, Integer b){ System.out.println(a == b); S

package Dec2016; import java.util.Arrays; public class Ques1219 { public static void main(String[] args) { int num = 2; Dog[] dogs01 = new Dog[num]; // dogs01中有两只狗 for(int i = 0; i < num; i++){ dogs01[i] = new Dog(i, Color.values()[i]); } Dog[] dogs0

package Dec2016; import java.util.ArrayList; import java.util.List; public class Ques1216 { public static void main(String[] args) { List<String> list01 = new ArrayList<String>(); List<Integer> list02 = new ArrayList<Integer>(); Sy

package Dec2016; public class Ques1215 { static final int num1 = 2; static final int num2 = 3; static int num3 = 2; static int num4 = 3; public static void main(String[] args){ int result1 = num1 * num2; // 1 int result2 = num3 * num4; // 2 } } 今日问题:

package Dec2016; import java.util.ArrayList; import java.util.List; public class Ques1214 { public static void main(String[] args){ final List<String> tickets = new ArrayList<String>(); for(int i = 0; i < 1000; i++){ tickets.add("高铁票-&