完美枚举

public enum TransportType {TCP(0), UDP(1), TLS(2);private int value;TransportType(int value) {this.value = value;}public int getValue() {return value;}public void setValue(int value) {this.value = value;}public static TransportType getInstance(int transportType) {switch (transportType) {case 0:return TransportType.TCP;case 1:return TransportType.UDP;case 2:return TransportType.TLS;default:return TransportType.TCP;}}}