Question

我有以下数据类型的数据结构如下：

Name                   Type   
Keyval                 String        //This is the key element
x                      Float           
x2                     Float                
result                 Float
performance            String

我想将其存储到HashMap，其中Key为keyval，其他所有信息（x,x2,result,performance）为相应的keyval。

输出示例：

[Keyval=com.a.service, x=0.05, x2=0.07, result=0.02, performance = IMPROVED]
[Keyval=com.b.service, x=0.03, x2=0.07, result=0.04, performance = IMPROVED]
[Keyval=com.c.service, x=0.15, x2=0.07, result=0.08, performance = DEGRADED]

如何存储它以及如何访问它？

Answer 1

您需要将所有元素存储在类（和构造函数）中：

public class Element {
    float x;
    float x2;
    float result;
    String performance;

    public Element(float x, float x2, float result, String performance) {
        this.x = x;
        this.x2 = x2;
        this.result = result;
        this.performance = performance;
    }

    @Override
    public String toString() {
        return "Element{" + "x=" + x + ", x2=" + x2 + ", result=" + result + ", performance=" + performance + '}';
    }
}

要像这样使用：

 public static void main(String[] args) {
        HashMap<String, Element> map = new HashMap<String, Element>();
        map.put("com.a.service", new Element(0.05, 0.07, 0.02, "IMPROVED"));
        //...
        Element a = map.get("com.a.service"); //x=0.05, x2=0.07, result=0.02, performance = IMPROVED
}

取回元素;）

Answer 2

您可以拥有Map<String, CustomObject> map类型的地图。您的CustomObject POJO看起来像;

public class CustomObject {

 Float x;
 Float x2;
 Float result;
 String performance;

 // constructor , setter and getters
}

您可以检索调用值

CustomObject object = map.get('keyValue');

Answer 3

您可以这样做：

import java.util.HashMap;
import java.util.Map;


public class Value{
       String performance;
       float x, x2, result;

       public Value(float x, float x2, float result, String performance) {
        this.performance = performance;
        this.x = x;
        this.x2 = x2;
        this.result = result;
       }

    public static void main(String[] args) {
        Map<String, Value> map = new HashMap<>();

        // to add values
        map.put("com.a.service", new Value(0.03f, 0.07f, 0.04f, "IMPROVED"));

        // to access them
        Value value = map.get("com.a.service");

        System.out.printf("KeyValue= com.a.service , X= %.2f, X2= %.2f, Result= %.2f, Performance= %s",
                                         value.x, value.x2, value.result, value.performance ); 
    }
}

<强>输出

KeyValue= com.a.service , X= 0.03, X2= 0.07, Result= 0.04, Performance= IMPROVED

Answer 4

创建一个包含以下私有字段变量的类WrapperClass：

x                      Float           
x2                     Float                
result                 Float
performance            String

和构造函数：

public WrapperClass(Float x, Float x2, Float result, String performance) {
     this.x = x;
     this.x2 = x2;
     this.result = result;
     this.performance = performance; 
}

然后定义Map<KeyVal, WrapperClass> myMap = new HashMap<>();

myMap.put("com.a.service", new WrapperClass(0.5,0.07,0.02,IMRPOVED));
myMap.put("com.b.service", new WrapperClass(0.03,0.07,0.04,IMRPOVED));

依旧......

现在您可以获得myMap.get("com.a.service")，它将返回WrapperClass个对象。

我希望这能回答你的问题。

使用单个密钥在HashMap中存储具有不同数据类型的数据

4 个答案: