49 lines
1.7 KiB
Java
49 lines
1.7 KiB
Java
package org.example;
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import org.example.domain.Student;
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import java.math.BigDecimal;
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import java.util.HashMap;
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import java.util.Map;
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public class StudentApplication {
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public static void main(String[] args) {
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// 设置编码（仅在需要时启用）
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try {
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System.setOut(new java.io.PrintStream(System.out,true,"UTF-8"));
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} catch (java.io.UnsupportedEncodingException e) {
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System.err.println("无法设置UTF-8编码：" + e.getMessage());
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}
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//创建HashMap对象
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HashMap<Integer, Student> studentHashMap = new HashMap<>();
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//创建两个学生对象
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Student studentOne = new Student(1, "梦钰", 22, "男", new BigDecimal(100));
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Student studentTwo = new Student(2, "钰萍", 18, "女", new BigDecimal(100));
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//保存到HashMap集合中，键为学生编号，值为学生对象
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studentHashMap.put(studentOne.getStudentId(),studentOne);
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studentHashMap.put(studentTwo.getStudentId(),studentTwo);
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System.out.println("第一种entrySet遍历方法:");
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for (Map.Entry<Integer, Student> studentEntry : studentHashMap.entrySet()) {
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System.out.println("key：" + studentEntry.getKey() + " value：" + studentEntry.getValue());
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}
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System.out.println("\n第二种keySet遍历方法:");
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for (Integer student : studentHashMap.keySet()) {
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System.out.println("key：" + student + " value：" + studentHashMap.get(student));
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}
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System.out.println("\n第三种values遍历方法:");
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for (Student student : studentHashMap.values()) {
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System.out.println( " value：" + student);
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}
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}
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}
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