Question

当我反映genericType时，我有一些问题。首先，我有一个像这样的类声明：

 System.out.print("Enter name:");
 name=sc.nextLine();

 System.out.print("Enter nric: ");
 nric=sc.nextLine();

 System.out.print("Enter age: ");
 age=sc.nextInt();
 sc.nextLine();// for consuming the nextLine

 System.out.print("Enter gender(male/female): ");
 gender=sc.nextLine();

 System.out.print("Enter weight:");
 weight=sc.nextInt();

 System.out.print("Enter height: ");
 height=sc.nextDouble();

T是：

public class JoyPageWebDTO<T> {
    private int recordCount;
    private int pageSize;
    private int pageIndex;
    private List<T> records;
}

请求后的JoyPageWebDTO结果如下： [http://i.stack.imgur.com/zeK1O.jpg][1]

问题是如何从public class AuditSpuWebDTO implements Serializable { private String indications; private String forbidden; private int shopID; private String shopName; private String city; private Date updateTime; private int auditStatus; private String auditContent; }获取T（AuditSpuWebDTO）？我希望得到JoyPageWebDTO的值。我写了一些代码来处理这个问题，然而，失败了！

AuditSpuWebDTO

当我反映泛型类型：来自List的T时，结果的类型为public static void reflect(Class<?> clazz) { for (Field field : clazz.getDeclaredFields()) { //get the static type of the field Class<?> fieldType = field.getType(); //if it's String, if (fieldType == String.class) { // save/use field } //if it's String[], else if (fieldType == String[].class) { // save/use field } //if it's List or a subtype of List, else if (List.class.isAssignableFrom(fieldType)) { //get the type as generic ParameterizedType fieldGenericType = (ParameterizedType) field.getGenericType(); //get it's first type parameter Type type = fieldGenericType.getActualTypeArguments()[0]; Class<?> fieldTypeParameterClazz; if (type instanceof ParameterizedType) { fieldTypeParameterClazz = (Class<?>) ((ParameterizedType) type).getRawType(); } else if(type instanceof TypeVariable){ //todo how to get the class???? }else{ fieldTypeParameterClazz = (Class<?>) type; } //if the type parameter is String, if (fieldTypeParameterClazz == String.class) { // save/use field } } } }，如何从TypeVariable获取Class<?>？我标记的TypeVariable是我的关键问题。

Answer 1

List唯一了解它的通用类型是它的名称为T

由于Java使用类型擦除，因此无法在运行时获取此信息。可以获得的是当您将特定类型编译到类中时，例如

// create a subclass of ArrayList with a specific type.
List<String> list = new ArrayList<String>() { };

但是，普通List或ArrayList没有编译到该类中的类型，因此无法从中检索更多信息。

我如何反映Class <t>的List <t>并获取T的内容？

1 个答案: