【简易版】HashMap（增删改查）

package com.java.demo_9;

/**
 * Student类
 * @author liupeng
 *
 */
public class Student {
    
    private String stuName;
    private String classCord;
    private String stuNumber;
    public String getStuName() {
        return stuName;
    }
    public void setStuName(String stuName) {
        this.stuName = stuName;
    }
    public String getClassCord() {
        return classCord;
    }
    public void setClassCord(String classCord) {
        this.classCord = classCord;
    }
    public String getStuNumber() {
        return stuNumber;
    }
    public void setStuNumber(String stuNumber) {
        this.stuNumber = stuNumber;
    }
    public Student() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Student(String stuName,String stuNumber,String classCord) {
        super();
        this.stuName = stuName;
        this.classCord = classCord;
        this.stuNumber = stuNumber;
    }
    @Override
    public String toString() {
        return "学员名称:" + stuName + ", 学员编号:"
        + stuNumber + ", 班级番号:" + classCord;
    }
    
    

}

 1 package com.java.demo_9;
 2 
 3 import java.util.HashMap;
 4 import java.util.Scanner;
 5 
 6 import com.java.demo_9.Student;
 7 
 8 public class HashMapTest {
 9     public static void main(String[] args) {
10         HashMap map = new HashMap();
11 
12         /**
13          * 通过for循环创建多位对象
14          */
15 /*         for(int i=1;i<=10;i++){ 
16              Student student = new Student("student"+i,"cn00"+i,"s100"+i); 
17              map.put("student"+i, student); }*/
18          
19         /**
20          * 逐一添加元素
21          */
22         System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
23         System.out.println("\t\t<学员信息一览表>\t\t");
24         System.out.println();
25         Student st1 = new Student("王小天", "cn0001", "class0001");
26         Student st2 = new Student("张天爱", "cn0002", "class0002");
27         Student st3 = new Student("武则天", "cn0003", "class0003");
28         Student st4 = new Student("小钢炮", "cn0004", "class0005");
29         
30         map.put("王小天", st1);
31         map.put("张天爱", st2);
32         map.put("武则天", st3);
33         map.put("小钢炮", st4);
34 
35         for (Object key : map.keySet()) {
36             // System.out.println(key);
37             Student value = (Student) map.get(key);
38             System.out.println(key + ":" + value);
39         }
40         
41         System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
42         System.out.println();
43         
44         /**
45          *    查询某个元素
46          */
47 
48         Scanner input = new Scanner(System.in);
49         System.out.print("请输入查找的学员名称:");
50         String stuName = input.next();
51 
52         Student stu = (Student) map.get(stuName);
53         if (stu == null) {
54             System.out.println();
55             System.out.println("对不起,无此人信息.");
56         } else {
57             System.out.println();
58             System.out.println(stu);
59 
60         }
61     }
62 
63 }

 1 package com.java.demo_9;
 2 
 3 import java.util.HashMap;
 4 import java.util.Scanner;
 5 
 6 import com.java.demo_9.Student;
 7 
 8 public class HashMapTest {
 9     public static void main(String[] args) {
10         HashMap map = new HashMap();
11 
12         /**
13          * 通过for循环创建多位对象
14          */
15 /*         for(int i=1;i<=10;i++){ 
16              Student student = new Student("student"+i,"cn00"+i,"s100"+i); 
17              map.put("student"+i, student); }*/
18          
19         /**
20          * 逐一添加元素
21          */
22         System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
23         System.out.println("\t\t<学员信息一览表>\t\t");
24         System.out.println();
25         Student st1 = new Student("王小天", "cn0001", "class0001");
26         Student st2 = new Student("张天爱", "cn0002", "class0002");
27         Student st3 = new Student("武则天", "cn0003", "class0003");
28         Student st4 = new Student("小钢炮", "cn0004", "class0005");
29         Student st5 = new Student("屠龙刀", "cn0005", "class0006");
30         
31         map.put("王小天", st1);
32         map.put("张天爱", st2);
33         map.put("武则天", st3);
34         map.put("小钢炮", st4);
35         map.put("屠龙刀", st5);
36 
37         for (Object key : map.keySet()) {
38             // System.out.println(key);
39             Student value = (Student) map.get(key);
40             System.out.println(key + ":" + value);
41         }
42         
43         System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
44 
45         /**
46          * 修改
47          * 
48          */
49         Scanner input = new Scanner(System.in);
50         System.out.print("请输入查找的学员名称:");
51         String stuName = input.next();
52 
53         Student stu = (Student) map.get(stuName);
54         if (stu == null) {
55             System.out.println();
56             System.out.println("对不起,无此人信息.");
57         } else {
58             System.out.println();
59             System.out.println(stu);
60             System.out.println();
61             System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
62             System.out.print("请输入修改学员的学员编号:");
63             String stuNo = input.next();
64             
65             stu.setStuNumber(stuNo);    //通过getters,setters中的.setStuNumber()方法进行修改.()中传入的是键盘输入进来的内容.
66             map.put(stuName, stu);        //修改完之后还要put到HashMap中去才可以.
67         }
68         System.out.println();
69         for (Object key : map.keySet()) {
70             // System.out.println(key);
71             Student value = (Student) map.get(key);
72             System.out.println(key + ":" + value);
73         }
74         
75     }
76 
77 }

package com.java.demo_9;

import java.util.HashMap;
import java.util.Scanner;

import com.java.demo_9.Student;

public class HashMapTest {
    public static void main(String[] args) {
        HashMap map = new HashMap();

        /**
         * 通过for循环创建多位对象
         */
/*         for(int i=1;i<=10;i++){ 
             Student student = new Student("student"+i,"cn00"+i,"s100"+i); 
             map.put("student"+i, student); }*/
         
        /**
         * 逐一添加元素
         */
        System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        System.out.println("\t\t<学员信息一览表>\t\t");
        System.out.println();
        Student st1 = new Student("王小天", "cn0001", "class0001");
        Student st2 = new Student("张天爱", "cn0002", "class0002");
        Student st3 = new Student("武则天", "cn0003", "class0003");
        Student st4 = new Student("小钢炮", "cn0004", "class0004");
        Student st5 = new Student("屠龙刀", "cn0005", "class0005");
        
        map.put("王小天", st1);
        map.put("张天爱", st2);
        map.put("武则天", st3);
        map.put("小钢炮", st4);
        map.put("屠龙刀", st5);

        for (Object key : map.keySet()) {
            // System.out.println(key);
            Student value = (Student) map.get(key);
            System.out.println(key + ":" + value);
        }
        
        /**
         * 删除
         * 直接通过HashMap中的.remove方法删除.
         */
        
        Scanner input = new Scanner(System.in);
        System.out.print("请输入要开除的学员名称:");
        String stuName = input.next();

        Student stu = (Student) map.get(stuName);
        if (stu == null) {
            System.out.println();
            System.out.println("对不起,无此人信息.");
            return; //如果没有找到对象,直接退出整个循环.不走下面的代码.
        } else {
            System.out.println();
            System.out.print("您确定要删除该学员吗? [确定]:y,[取消]:n");
            String isok = input.next();
            if(isok.equals("y")){
                map.remove(stuName);
                System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
                for (Object key : map.keySet()) {
                    // System.out.println(key);
                    Student value = (Student) map.get(key);
                    System.out.println(key + ":" + value);
                }
            }else{
                System.out.println("该操作已被撤回!");
            }
            
        }
        
    }

}

package com.java.demo_9;

import java.util.HashMap;
import java.util.Scanner;

import com.java.demo_9.Student;

public class HashMapTest {
    public static void main(String[] args) {
        HashMap map = new HashMap();

        /**
         * 通过for循环创建多位对象
         */
/*         for(int i=1;i<=10;i++){ 
             Student student = new Student("student"+i,"cn00"+i,"s100"+i); 
             map.put("student"+i, student); }*/
         
        /**
         * 逐一添加元素
         */
        System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        System.out.println("\t\t<学员信息一览表>\t\t");
        System.out.println();
        Student st1 = new Student("王小天", "cn0001", "class0001");
        Student st2 = new Student("张天爱", "cn0002", "class0002");
        Student st3 = new Student("武则天", "cn0003", "class0003");
        Student st4 = new Student("小钢炮", "cn0004", "class0004");
        Student st5 = new Student("屠龙刀", "cn0005", "class0005");
        
        map.put("王小天", st1);
        map.put("张天爱", st2);
        map.put("武则天", st3);
        map.put("小钢炮", st4);
        map.put("屠龙刀", st5);

        for (Object key : map.keySet()) {
            // System.out.println(key);
            Student value = (Student) map.get(key);
            System.out.println(key + ":" + value);
        }
        
        System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        System.out.println();
        
        /**
         *    查询某个元素
         *(通过stuName来查找)
         */

/*        Scanner input = new Scanner(System.in);
        System.out.print("请输入查找的学员名称:");
        String stuName = input.next();

        Student stu = (Student) map.get(stuName);
        if (stu == null) {
            System.out.println();
            System.out.println("对不起,无此人信息.");
        } else {
            System.out.println();
            System.out.println(stu);

        }*/
        
        /**
         * 修改
         * 
         *//*
        Scanner input = new Scanner(System.in);
        System.out.print("请输入查找的学员名称:");
        String stuName = input.next();

        Student stu = (Student) map.get(stuName);
        if (stu == null) {
            System.out.println();
            System.out.println("对不起,无此人信息.");
        } else {
            System.out.println();
            System.out.println(stu);
            System.out.println();
            System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
            System.out.print("请输入修改学员的学员编号:");
            String stuNo = input.next();
            
            stu.setStuNumber(stuNo);    //通过getters,setters中的.setStuNumber()方法进行修改.()中传入的是键盘输入进来的内容.
            map.put(stuName, stu);        //修改完之后还要put到HashMap中去才可以.
        }
        System.out.println();
        for (Object key : map.keySet()) {
            // System.out.println(key);
            Student value = (Student) map.get(key);
            System.out.println(key + ":" + value);
        }
*/        
/*        *//**
         * 删除
         * 直接通过HashMap中的.remove方法删除.
         *//*
        
        Scanner input = new Scanner(System.in);
        System.out.print("请输入要开除的学员名称:");
        String stuName = input.next();

        Student stu = (Student) map.get(stuName);
        if (stu == null) {
            System.out.println();
            System.out.println("对不起,无此人信息.");
            return; //如果没有找到对象,直接退出整个循环.不走下面的代码.
        } else {
            System.out.println();
            map.remove(stuName);
        }
        System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        for (Object key : map.keySet()) {
            // System.out.println(key);
            Student value = (Student) map.get(key);
            System.out.println(key + ":" + value);
        }*/
        
        /**
         * 追加
         */
        
        Scanner input = new Scanner(System.in);
        System.out.print("请输入追加的学员名称:");
        String stuName = input.next();
        System.out.print("请输入追加的学员的学员编号:");
        String stuNumber = input.next();
        System.out.print("请输入追加的学员的教室:");
        String classCord = input.next();
        Student student = new Student(stuName, stuNumber, classCord);
        
        map.put(stuName, student);
        
        System.out.println();
        System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
        for (Object key : map.keySet()) {
            // System.out.println(key);
            Student value = (Student) map.get(key);
            System.out.println(key + ":" + value);
        }
        
        
    }

}