Java-如何使用枚举/工厂模式基于字符串调用相应类的方法

是的，我在网上读了很多例子，但我没有找到一种方法来调用基于字符串值的方法。也许我没有用正确的方式寻找。。。我写了所有代码，但不知道如何调用该方法。 仅供参考：我不想使用

if-else

或

开关盒

以下是我想要的： 我从数据库中获取读卡器类型为String。我必须调用相应的类的方法

我的代码：

LoginPanel.java

public class LoginPanel {
    public static void main(String args[]) {

        String readerType = "Omnikey5427-CK"; // I get this ("Omnikey5427-CK" or "Omnikey5427-G2") from a database as String 

        // I WANT TO CALL getCardNumber() method of respective class


    }
}

public interface ISmartCardReader {

    public Integer getCardNumber();

}

public class Omnikey5427G2 implements ISmartCardReader {

    public Omnikey5427G2() {
        System.out.println("G222222222222222...");
    }

    public Integer getCardNumber() {
        return 222;
    }
}

public class Omnikey5427CK implements ISmartCardReader {

    public Omnikey5427CK() {
        System.out.println("CKKKKKKKKKKKKKKK...");
    }

    public Integer getCardNumber() {
        return 111;
    }
}

public enum SmacrtCardEnumFactory {

    OMNIKEY5427CK("Omnikey5427-CK") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427CK();
        }
    },
    OMNIKEY5427G2("Omnikey5427-G2") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427G2();
        }
    };

    private String cardReaderName;

    private SmacrtCardEnumFactory(String cardReaderName) {
        this.cardReaderName = cardReaderName;
    }

    public String cardReaderName() {
        return cardReaderName;
    }

}

ISmartCardReader.java

public class LoginPanel {
    public static void main(String args[]) {

        String readerType = "Omnikey5427-CK"; // I get this ("Omnikey5427-CK" or "Omnikey5427-G2") from a database as String 

        // I WANT TO CALL getCardNumber() method of respective class


    }
}

public interface ISmartCardReader {

    public Integer getCardNumber();

}

public class Omnikey5427G2 implements ISmartCardReader {

    public Omnikey5427G2() {
        System.out.println("G222222222222222...");
    }

    public Integer getCardNumber() {
        return 222;
    }
}

public class Omnikey5427CK implements ISmartCardReader {

    public Omnikey5427CK() {
        System.out.println("CKKKKKKKKKKKKKKK...");
    }

    public Integer getCardNumber() {
        return 111;
    }
}

public enum SmacrtCardEnumFactory {

    OMNIKEY5427CK("Omnikey5427-CK") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427CK();
        }
    },
    OMNIKEY5427G2("Omnikey5427-G2") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427G2();
        }
    };

    private String cardReaderName;

    private SmacrtCardEnumFactory(String cardReaderName) {
        this.cardReaderName = cardReaderName;
    }

    public String cardReaderName() {
        return cardReaderName;
    }

}

Omnikey5427G2.java

public class LoginPanel {
    public static void main(String args[]) {

        String readerType = "Omnikey5427-CK"; // I get this ("Omnikey5427-CK" or "Omnikey5427-G2") from a database as String 

        // I WANT TO CALL getCardNumber() method of respective class


    }
}

public interface ISmartCardReader {

    public Integer getCardNumber();

}

public class Omnikey5427G2 implements ISmartCardReader {

    public Omnikey5427G2() {
        System.out.println("G222222222222222...");
    }

    public Integer getCardNumber() {
        return 222;
    }
}

public class Omnikey5427CK implements ISmartCardReader {

    public Omnikey5427CK() {
        System.out.println("CKKKKKKKKKKKKKKK...");
    }

    public Integer getCardNumber() {
        return 111;
    }
}

public enum SmacrtCardEnumFactory {

    OMNIKEY5427CK("Omnikey5427-CK") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427CK();
        }
    },
    OMNIKEY5427G2("Omnikey5427-G2") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427G2();
        }
    };

    private String cardReaderName;

    private SmacrtCardEnumFactory(String cardReaderName) {
        this.cardReaderName = cardReaderName;
    }

    public String cardReaderName() {
        return cardReaderName;
    }

}

Omnikey5427CK.java

public class LoginPanel {
    public static void main(String args[]) {

        String readerType = "Omnikey5427-CK"; // I get this ("Omnikey5427-CK" or "Omnikey5427-G2") from a database as String 

        // I WANT TO CALL getCardNumber() method of respective class


    }
}

public interface ISmartCardReader {

    public Integer getCardNumber();

}

public class Omnikey5427G2 implements ISmartCardReader {

    public Omnikey5427G2() {
        System.out.println("G222222222222222...");
    }

    public Integer getCardNumber() {
        return 222;
    }
}

public class Omnikey5427CK implements ISmartCardReader {

    public Omnikey5427CK() {
        System.out.println("CKKKKKKKKKKKKKKK...");
    }

    public Integer getCardNumber() {
        return 111;
    }
}

public enum SmacrtCardEnumFactory {

    OMNIKEY5427CK("Omnikey5427-CK") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427CK();
        }
    },
    OMNIKEY5427G2("Omnikey5427-G2") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427G2();
        }
    };

    private String cardReaderName;

    private SmacrtCardEnumFactory(String cardReaderName) {
        this.cardReaderName = cardReaderName;
    }

    public String cardReaderName() {
        return cardReaderName;
    }

}

smartcardenumfactory.java

public class LoginPanel {
    public static void main(String args[]) {

        String readerType = "Omnikey5427-CK"; // I get this ("Omnikey5427-CK" or "Omnikey5427-G2") from a database as String 

        // I WANT TO CALL getCardNumber() method of respective class


    }
}

public interface ISmartCardReader {

    public Integer getCardNumber();

}

public class Omnikey5427G2 implements ISmartCardReader {

    public Omnikey5427G2() {
        System.out.println("G222222222222222...");
    }

    public Integer getCardNumber() {
        return 222;
    }
}

public class Omnikey5427CK implements ISmartCardReader {

    public Omnikey5427CK() {
        System.out.println("CKKKKKKKKKKKKKKK...");
    }

    public Integer getCardNumber() {
        return 111;
    }
}

public enum SmacrtCardEnumFactory {

    OMNIKEY5427CK("Omnikey5427-CK") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427CK();
        }
    },
    OMNIKEY5427G2("Omnikey5427-G2") {
        public ISmartCardReader geInstance() {
            return new Omnikey5427G2();
        }
    };

    private String cardReaderName;

    private SmacrtCardEnumFactory(String cardReaderName) {
        this.cardReaderName = cardReaderName;
    }

    public String cardReaderName() {
        return cardReaderName;
    }

}

---

如果枚举实例名称与用于查找的字符串匹配，则可以使用枚举的valueOf（）函数（可以使用cardName.toUpper（）。您还可以为所有卡类型创建对象，并将其存储在哈希映射中，然后进行查找。您也可以编写一些fatory方法，但这将是if-then-else或switch-in

您可以迭代工厂的

值（）

，并获得与字符串匹配的值：

公共枚举SmactCardenumFactory{
//为简洁起见，省略了当前代码
公共静态getSmartCardReader（字符串名称）{
返回Arrays.stream（values（））
.filter（r->r.cardReaderName（）.equals（名称））
.map（SmactCardenumFactory:：getInstance（）；
.orElse（空）；
}
}

if（“test”.equals（myString））返回test（）；else if（“notTest”.equals（myString））返回notTest（））差不多probably@Stultuske-我不想使用

if else

或

开关大小写

您需要实现一个解析系统来将字符串转换为对应的枚举。您可以使用db字符串，去掉连字符，使其全部大写，然后调用

SmartCardEnumFactory.valueOf（ModifiedBString）

获取所需的实例，然后调用所需的适当方法。如果需要进行缩放，则需要确定标准，以便编写适当的解析器：确定命名约定，以便编写可缩放的解析器。如果没有约定/标准，则无法确定可能出现的角点情况当新版本发布时，会导致您更新代码。也许您可以将ann注释添加到每个包含自己的字符串表示的类中，然后工厂可以读取这些字符串表示？