diff --git "a/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Map.java" "b/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Map.java" new file mode 100644 index 0000000000000000000000000000000000000000..c39ad964b684244894e18db94cf46e9115231615 --- /dev/null +++ "b/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Map.java" @@ -0,0 +1,66 @@ +package com.java.minxi.java_20240515.java_2302_戴廷杰_2344310203; + +import java.util.HashMap; + +public class Map { + public static void main(String[] args) { + // 创建一个 `HashMap` 并添加至少3对键值对，键可以是字符串，值可以是整数 + HashMap hashMap=new HashMap<>(); + hashMap.put("a",1); + hashMap.put("b",2); + hashMap.put("c",3); + + // 使用键来获取对应的值，并打印出来。 + System.out.println(hashMap.get("a")); + + System.out.println("-----------------------"); + // 检查一个特定的键是否存在于 `HashMap` 中。 + if (hashMap.containsKey("a")) { + System.out.println("存在"); + }else { + System.out.println("不存在"); + } + + //遍历 `HashMap` 的键集合，并打印每个键。 + for (Object key : hashMap.keySet()){ + System.out.println(key); + } + System.out.println("-------------------"); + //遍历 `HashMap` 的值集合，并打印每个值。 + for (Object values : hashMap.values()) { + System.out.println(values); + } + System.out.println("---------------------------"); + //使用 `entrySet()` 遍历 `HashMap` 的所有键值对，并打印。 + System.out.println(hashMap); + System.out.println(hashMap.entrySet()); + + System.out.println("--------------"); + //对一个已存在的键更新其对应的值 + System.out.println(hashMap.put("a",4)); + + System.out.println("--------------------"); + // 移除一个特定的键值对，并确认它已被移除。 + hashMap.remove("a"); + if (hashMap.containsKey("a")) { + System.out.println("存在"); + }else { + System.out.println("不存在"); + } + + System.out.println("-------------------"); + //打印出 `HashMap` 的大小。 + System.out.println(hashMap.size()); + + System.out.println("------------------------"); + // 创建一个泛型 `HashMap`，键为自定义对象，值为字符串，并添加键值对。 + + + + + + } + + + +} diff --git "a/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Test.java" "b/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Test.java" new file mode 100644 index 0000000000000000000000000000000000000000..51c085c35c801911140fc5d3a21f3bb6fa958242 --- /dev/null +++ "b/work/com/java/minxi/java_20240515/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Test.java" @@ -0,0 +1,69 @@ +package com.java.minxi.java_20240515.java_2302_戴廷杰_2344310203; + +import java.util.HashSet; + +public class Test { + public static void main(String[] args) { + // 创建一个 `HashSet` 并添加至少5个不同的字符串元素 + HashSet hashSet=new HashSet<>(); + hashSet.add("apple1"); + hashSet.add("apple2"); + hashSet.add("apple3"); + hashSet.add("apple4"); + hashSet.add("apple5"); + System.out.println(hashSet); + + System.out.println("--------------------------"); + // 检查一个特定的字符串是否已经存在于你创建的 `HashSet` 中。 + System.out.println("是否有apple1："+hashSet.contains("apple1")); + + System.out.println("--------------------------"); + //从 `HashSet` 中移除一个已存在的元素，并确认它已被移除。 + hashSet.remove("apple1"); + System.out.println(hashSet); + System.out.println("------------------------------"); + + // 打印出 `HashSet` 的大小。 + System.out.println("大小为："+hashSet.size()); + System.out.println("--------------------"); + + //使用增强型 `for` 循环遍历 `HashSet` 并打印每个元素。 + for (String a:hashSet){ + System.out.println(a); + } + + System.out.println("--------------------------"); + //将 `HashSet` 转换为数组，并打印数组中的每个元素。 + hashSet.toArray(); + System.out.println(hashSet); + System.out.println("---------------------"); + + // 创建两个 `HashSet` 对象，实现它们的并集操作。 + HashSet hashSet2=new HashSet<>(); + hashSet2.add("apple6"); + hashSet2.add("apple7"); + System.out.println(hashSet2); + HashSet hashSet3=new HashSet<>(); + hashSet3.add("apple8"); + hashSet3.add("apple9"); + System.out.println(hashSet3); + hashSet2.addAll(hashSet3); + System.out.println("并集"+hashSet2); + + + System.out.println("------------------"); + //对上面创建的两个 `HashSet` 对象实现交集操作。 + hashSet2.retainAll(hashSet3); + System.out.println("交集"+hashSet2); + + + System.out.println("-------------------------"); + // 对上面创建的两个 `HashSet` 对象实现差集操作。 + hashSet2.removeAll(hashSet3); + System.out.println("差集"+hashSet2); + + + + + } +} diff --git "a/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/BigDecimal.java" "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/BigDecimal.java" new file mode 100644 index 0000000000000000000000000000000000000000..f1bd5caaeeb9180e582995eb83b91dd6a702a613 --- /dev/null +++ "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/BigDecimal.java" @@ -0,0 +1,11 @@ +package com.java.minxi.java_20240516.java_2302_戴廷杰_2344310203; + +public class BigDecimal { + public static void main(String[] args) { + + + + + } + +} diff --git "a/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Date.java" "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Date.java" new file mode 100644 index 0000000000000000000000000000000000000000..469efdaf71549b1cb899aadd099b56df8b0a0b57 --- /dev/null +++ "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Date.java" @@ -0,0 +1,34 @@ +package com.java.minxi.java_20240516.java_2302_戴廷杰_2344310203; + +import java.text.SimpleDateFormat; +import java.time.LocalDate; + +public class Date { + public static void main(String[] args) { + Date date =new Date(); + System.out.println(date.toString()); + + LocalDate current=LocalDate.now(); + System.out.println(current+"的年份："+current.getYear()); + System.out.println(current+"的月份："+current.getMonth()); + System.out.println(current+"的天数："+current.getDayOfMonth()); + System.out.println(); + + + + Date a=new Date(); + SimpleDateFormat aa=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); + System.out.println("当前时间为："+aa.format(a)); + + + Date current1=new Date(); + SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); + String dateString =formatter.format(current1); + + + + + } + + +} diff --git "a/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Math.java" "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Math.java" new file mode 100644 index 0000000000000000000000000000000000000000..5ab457ca630fa960db970f67d33257704dcb4d8e --- /dev/null +++ "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Math.java" @@ -0,0 +1,47 @@ +package com.java.minxi.java_20240516.java_2302_戴廷杰_2344310203; + +import java.util.Arrays; +import java.util.Scanner; +import java.util.stream.IntStream; + +public class Math { + public static void main(String[] args) { + + Scanner scanner = new Scanner(System.in); + System.out.println("请输入一个数字："); + double num = scanner.nextDouble(); + double num0 = java.lang.Math.abs(num); + System.out.println("绝对值为：" + num0); + + int num1 = 1; + int num2 = 2; + int num3 = 3; + + int min = java.lang.Math.min(num1,java.lang.Math.max(num2,num3)); + int max = java.lang.Math.max(num1, java.lang.Math.max(num2, num3)); + + System.out.println("最小值为：" + min); + System.out.println("最大值为：" + max); + + System.out.println("请输入一个浮点数："); + double num4 = scanner.nextDouble(); + long a = java.lang.Math.round(num4); + System.out.println("四舍五入的整数为：" + a); + + System.out.println("请输入一个最大值："); + int maxnum = scanner.nextInt(); + double randomNum = java.lang.Math.random(); + System.out.println("生成的随机数为：" + randomNum); + System.out.println("相乘后为" + randomNum * maxnum); + + + int[] numbers ={6,2,29,47,80}; + IntStream stream= Arrays.stream(numbers); + double average =stream.average().getAsDouble(); + System.out.println("平均数为："+average); + + + + + } +} diff --git "a/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Person.java" "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Person.java" new file mode 100644 index 0000000000000000000000000000000000000000..ef487e44570e177fb6122dd6887076ab68dbe6e6 --- /dev/null +++ "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Person.java" @@ -0,0 +1,36 @@ +package com.java.minxi.java_20240516.java_2302_戴廷杰_2344310203; + +public class Person { + // 重写 `toString` 方法 +// 创建一个 `Person` 类，包含 `name` 和 `age` 属性。 + // 重写 `toString` 方法，使其返回一个字符串，包含对象的 `name` 和 `age` + private String name; + private int age; + + public Person(String name, int age) { + this.name = name; + this.age = age; + } + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + + public int getAge() { + return age; + } + + public void setAge(int age) { + this.age = age; + } + @Override + public String toString() { + return name + age; + } + + + +} diff --git "a/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Sting.java" "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Sting.java" new file mode 100644 index 0000000000000000000000000000000000000000..f6a736ffae416ba0322eb8eb7e66354072c8a76e --- /dev/null +++ "b/work/com/java/minxi/java_20240516/java_2302_\346\210\264\345\273\267\346\235\260_2344310203/Sting.java" @@ -0,0 +1,18 @@ +package com.java.minxi.java_20240516.java_2302_戴廷杰_2344310203; + +public class Sting { + public static void main(String[] args) { + // 1. 字符串连接 +// - 编写一个程序，连接两个字符串，并输出结果。 + String a="11111"; + String b="22222"; + String c=a+b; + System.out.println(c); + + + + + + } + +}