添加代码后出现错误信息是Cannot resolve method 'Values()'
时间: 2023-12-30 15:02:36 浏览: 20
抱歉我的错误,`values()`应该是小写字母。请将代码中的`Values()`改为`values()`即可,代码如下所示:
```
public void loop() {
for (RealTimeData data : RealTimeData.values()) {
System.out.println(data.name() + ":" + data.getValue());
}
}
```
这样就能正确地遍历`RealTimeData`枚举类型的所有取值,并输出对应的名称和值了。
相关问题
public void copyProperties(Object source, Object target) { BeanWrapper sourceWrapper = PropertyAccessorFactory.forBeanPropertyAccess(source); BeanWrapper targetWrapper = PropertyAccessorFactory.forBeanPropertyAccess(target); PropertyValues sourceValues = sourceWrapper.getPropertyValues(); for (PropertyValue pv : sourceValues.getPropertyValues()) { String propertyName = pv.getName(); if (propertyName.startsWith(prefix)) { String targetPropertyName = propertyName.substring(prefix.length()); if (targetWrapper.isWritableProperty(targetPropertyName)) { Object value = pv.getValue(); targetWrapper.setPropertyValue(targetPropertyName, value); } }代码报错:Cannot resolve method 'getPropertyValues' in 'BeanWrapper'
这个错误提示是因为BeanWrapper类中没有getPropertyValues()方法,它被替换成了getPropertyValues(PropertyFilter filter)方法,该方法需要传入一个PropertyFilter过滤器,用于过滤掉不需要复制的属性。
因此,你可以将原来的代码:
```
PropertyValues sourceValues = sourceWrapper.getPropertyValues();
```
替换成:
```
PropertyValues sourceValues = sourceWrapper.getPropertyValues(null, true);
```
其中,第一个参数为过滤器,第二个参数表示是否包括只读属性。这样就可以解决这个报错了。
hashmap cannot be cast to list
The error "hashmap cannot be cast to list" occurs when you try to assign or convert a HashMap object to a List object directly, but they are incompatible types.
HashMap is a key-value pair data structure that implements the Map interface, while List is an ordered collection of elements that allows duplicates and implements the List interface.
To resolve this issue, you need to convert the HashMap into a List by extracting the values or keys from the HashMap and adding them to the List. Here's an example:
```java
import java.util.*;
public class Example {
public static void main(String[] args) {
HashMap<Integer, String> hashMap = new HashMap<>();
hashMap.put(1, "One");
hashMap.put(2, "Two");
hashMap.put(3, "Three");
List<String> list = new ArrayList<>(hashMap.values()); // OR
// List<Integer> list = new ArrayList<>(hashMap.keySet());
System.out.println(list);
}
}
```
In this example, we extract the values from the HashMap using the `values()` method and create a new ArrayList with those values. Alternatively, you can use `keySet()` method to extract the keys and add them to the List.
Make sure to choose the appropriate data type for your List based on the values or keys you want to extract from the HashMap.
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