java 关于枚举类型 valueOf方法

  在java中使用枚举类型时

public enum TestEnum{

TEST1("test1"),

TEST2("test2"),

TEST3("test3"),

TEST4("test4"),;

private TestEnum(String code) {

this.code = code;

}

private String code;

public String getText() {

return this.getText();

}

public String getCode() {

return this.code;

}

}

当想要通过一个String获取枚举时，默认可以使用枚举本身提供的 ValueOf，但是是需要两个参数，

特殊的地方是，String类型的valueOf(String) 方法 ，枚举给隐士提供一个静态方法。

其他类型就需要自己定义喽。

TestEnum.valueOf("TEST1");形式获取

以下是API描述。

public static <T extends Enum<T>> T valueOf(Class<T> enumType,
                            String name)

Returns the enum constant of the specified enum type with the specified name. The name must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Note that for a particular enum type T, the implicitly declared public static T valueOf(String) method on that enum may be used instead of this method to map from a name to the corresponding enum constant. All the constants of an enum type can be obtained by calling the implicit public static T[] values() method of that type.

Type Parameters:

T - The enum type whose constant is to be returned

Parameters:

enumType - the  Class object of the enum type from which to return a constant

name - the name of the constant to return

Returns:

the enum constant of the specified enum type with the specified name

Throws:

IllegalArgumentException - if the specified enum type has no constant with the specified name, or the specified class object does not represent an enum type

NullPointerException - if  enumType or  name is null

Since:

1.5