如何从Java的HashMap中获取对象 [英] How to get an object from a HashMap in Java

问题描述

我试图从给定密钥的HashMap中获取Test对象的速度，但我不太确定如何去做。我试过这种方式，但它的错误：

  hash.values（）。getSpeed（）; 
  

有什么帮助吗？谢谢

  class Test {
 
 private String id; 
私人字符串名称; 
 private int speed; 
 
 public Test（String id，String name，int speed）{
 this.id = id; 
 this.name = name; 
 this.speed =速度; 
 
} 
 
 public String getId（）{
 return id; 
} 
 
 public String getName（）{
 return name; 
 
} 
 
 public int getSpeed（）{
 return speed; 
 
 
 public class Driver {
 public static void main（String [] args）{
 HashMap< String，Test> hash = new HashMap< String，Test>（）; 
 
测试c1; 
测试c2; 
 
 c1 = new Test（Z，B，4）; 
 c2 = new Test（Y，D，7）; 
 hash.put（A，c1）; 
 hash.put（C，c2）; 
 
 
 $ / code $ / pre 
 
解决方案
 
 测试c1; 
测试c2; 
 
 c1 = new Test（Z，B，4）; 
 c2 = new Test（Y，D，7）; 
 hash.put（A，c1）; 
 hash.put（C，c2）; 
 
 Test getC1 =（Test）hash.get（A）; 
 Test getC2 =（Test）hash.get（C）; 
  
 
I'm trying to get the speed of a Test object from a HashMap when given the key but I'm not quite sure how to do it. I tried this way but its wrong:
hash.values().getSpeed();
Any help? Thanks
class Test {

            private String id;
            private String name;
            private int speed;

            public Test(String id, String name, int speed) {
                this.id = id;
                this.name = name;
                this.speed = speed;

            }

            public String getId() {
                return id;
            }

            public String getName() {
                return name;

            }

            public int getSpeed() {
                return speed;
            }
        }    
    public class Driver {    
    public static void main(String[] args) {
        HashMap<String, Test> hash = new HashMap<String, Test>();

            Test c1;
            Test c2;

            c1 = new Test("Z", "B", 4);
            c2 = new Test("Y", "D", 7);
            hash.put("A", c1);
            hash.put("C", c2);
    }
}

解决方案
Test c1;
Test c2;

c1 = new Test("Z", "B", 4);
c2 = new Test("Y", "D", 7);
hash.put("A", c1);
hash.put("C", c2);

Test getC1 = (Test)hash.get("A");
Test getC2 = (Test)hash.get("C");


                        
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