迭代LinkedHashMap显示编译错误

Question

Below is the code for AttributeValue class-

@JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
@JsonIgnoreProperties(ignoreUnknown=true)
public class AttributeValue<T> {
    private T value;                    // value
    private Date timestamp;             // timestamp
    String valueType = null;        // class type of the value object

    @Deprecated
    private int classNumber = 0;        // internal

    private static Logger s_logger = Logger.getInstance(BEAttributeValue.class);

    @JsonProperty("v")
    public T getValue() {
        if (valueType != null && !value.getClass().getName().equalsIgnoreCase(valueType)) {
            value = convert(value, valueType);
        }
        return value;
    }

    @JsonProperty("v")
    public void setValue(T value) {
        this.value = value;
    }

    private T convert(Object other, String classType) {
        T value = null;
        if (other != null) {
            IJsonMapper mapper = JsonMapperFactory.getInstance().getJsonMapper();
            try {
                String json = mapper.toJson(other);
                Class<T> className = (Class<T>)Class.forName(classType);
                value = mapper.toPojo(json, className);
            } catch (Exception e) {
                s_logger.log(LogLevel.ERROR, "BEAttributeValue::convert(), caught an exception: \n",e.getStackTrace());
            }       
        }
        return value;
    }
}

Problem Statement:-

Now I am trying to iterate over the list of AttributeValue with the below code-

for(AttributeValue<?> al: list) {

System.out.println(al.getValue());

}

When I inspect on al , I see value as LinkedHashMap<K,V> and when I print al.getValue() , it gives me this-

{predictedCatRev=0;101;1,1;201;2, predictedOvrallRev=77;2,0;1,16;3, sitePrftblty=77;2,0;1671679, topByrGms=12345.67, usrCurncy=1, vbsTopByrGmb=167167.67}

So I thought al.getValue will be a Map and I can iterate it like this-

for (Map.Entry<Integer, Integer> entry : al.getValue().entrySet()) {
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

But it is giving me compilation error at entrySet() with red color. And I am not sure how can I iterate over the value as clearly while inspection, I can see that as LinkedHashMap<K,V> .

Can anyone help me with this?

Answer 1

You need to do a cast . The compiler does not know that al.getValue() is of type Map<Integer, Integer> , so you have to tell him specifically:

for (Map.Entry<Integer, Integer> entry : ((Map<Integer, Integer>) al.getValue()).entrySet()) {