怎么处理Raw use of parameterized class
时间: 2023-09-27 21:09:07 浏览: 305
这个警告通常出现在使用泛型类时,没有指定泛型类型参数。要解决这个警告,可以在使用泛型类时指定泛型类型参数,例如:
```
List<String> list = new ArrayList<>();
```
另外,如果你确定使用的泛型类型参数是正确的,也可以使用@SuppressWarnings注解来忽略这个警告:
```
@SuppressWarnings("rawtypes")
List list = new ArrayList();
```
相关问题
Raw use of parameterized class 'ArrayList'Raw use of parameterized class 'ArrayList'
当你看到 "Raw use of parameterized class 'ArrayList'" 的警告时,这是Java编译器对于泛型的一种提示。在Java中,`ArrayList` 是一个泛型类,它的版本有 `<E>` 参数,其中 `E` 表示元素类型,如 `ArrayList<String>` 或 `ArrayList<Integer>`。然而,有时候代码中直接使用了 `ArrayList` 类名,没有指定具体的元素类型,这就被称为 "raw use"。
例如:
```java
List list = new ArrayList(); // 这是一个 raw 使用,因为没有指定元素类型
// 相比之下,下面这样就是正确的泛型使用
List<String> stringList = new ArrayList<>();
```
警告的原因是,不指定元素类型可能会导致类型安全的问题,特别是在处理大量数据或作为函数返回值时。为了避免这种警告,你应该始终明确地指定类型。如果你确实不想限制元素类型,可以使用 `ArrayList<Object>`,但这通常不是一个好的实践,因为它降低了代码的类型安全性。
Raw use of parameterized class
The raw use of a parameterized class refers to using the class without specifying the type parameter. In languages like Java or C#, parameterized classes allow you to create classes that can work with different types. However, if you use the class without specifying the type parameter, it is considered a raw use.
For example, let's say we have a generic class called `Box` that can hold any type of object:
```java
public class Box<T> {
private T value;
public void setValue(T value) {
this.value = value;
}
public T getValue() {
return value;
}
}
```
If we use this class without specifying the type parameter, it becomes a raw use:
```java
Box box = new Box(); // Raw use of Box
box.setValue("Hello"); // No type safety
String value = (String) box.getValue(); // Type casting required
```
In the above example, `Box box = new Box();` is a raw use because we are not specifying the type parameter. This results in the loss of type safety, as we can assign any type of value to the `value` field without any compiler checks. We also need to perform explicit type casting when retrieving the value.
It is generally recommended to avoid raw uses of parameterized classes as they bypass the type safety provided by generics and can lead to runtime errors or unexpected behavior.
阅读全文