Java 5 的新标准语法和用法详解集锦

Java 5 的新标准语法和用法详解集锦

Java 5 的新标准语法和用法详解集锦(需要在首选项-java-complier-compiler compliance level中设置为java5.0以上版本)


1,静态导入

public class Java5 {public static void main(String[] args) {Week weekday = Week.MON;System.out.println(weekday);System.out.println(weekday.nextDay());}}/** * 用普通类模拟实现枚举类型-星期 * @author qsuron - 博客:http://blog.csdn.net/qsuron */abstract class Week{private String conf;private Week(String conf){this.conf = conf;}/*建立NextDay()抽象方法，将NextDay方法的一堆if...else...转换成为 由子类去覆盖此方法*/public abstract Week nextDay();//建立公开的静态常量子类public final static Week MON = new Week("星期一"){public Week nextDay() {return TUE;}};public final static Week TUE = new Week("星期二"){public Week nextDay() {return WED;}};public final static Week WED = new Week("星期三"){public Week nextDay() {return THI;}};public final static Week THI = new Week("星期四"){public Week nextDay() {return FRI;}};public final static Week FRI = new Week("星期五"){public Week nextDay() {return STA;}};public final static Week STA = new Week("星期六"){public Week nextDay() {return SUM;}};public final static Week SUM = new Week("星期日"){public Week nextDay() {return MON;}};/*重写toString()方法*/public String toString() {return this.conf;}}/** * 使用JAVA5提供的枚举类型 - 基础用法和基本方法 * @author qsuron - 博客:http://blog.csdn.net/qsuron */public class Java5 {public static void main(String[] args) {Week w = Week.MON;System.out.println("toString - "+w);System.out.println("与MON比较 - "+w.compareTo(Week.MON));System.out.println("Nama - "+w.name());System.out.println("所在顺序 - "+w.ordinal());System.out.println("枚举数量 - "+Week.values().length);}public enum Week{MON,TUE,WED,THE,FRI,STA,SUM;}}/** * 使用JAVA5提供的枚举类型 - 构造方法 * 加上private String name  和  重新toString方法可以实现中文信息输出 * @author qsuron - 博客:http://blog.csdn.net/qsuron */public class Java5 {public static void main(String[] args) {System.out.println("MON(1),TUE(),WED,THE(1),FRI,STA,SUM();");Week w = Week.MON;System.out.println(w);}public enum Week{MON(1),TUE(),WED,THE(1),FRI,STA,SUM();private Week(){System.out.println("空构造函数");}private Week(int i){System.out.println("带参数构造函数");}}}/** * 使用JAVA5提供的枚举类型 - 抽象函数 * 让子类去覆盖抽象方法 - 实现Next()的功能 * @author qsuron - 博客:http://blog.csdn.net/qsuron */public class Java5 {public static void main(String[] args) {Week w = Week.MON;System.out.println(w.next());}public enum Week{//由于麻烦,只写2个星期数MON{public Week next(){return TUE;}},TUE{public Week next(){return MON;}};public abstract Week next();}}

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