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Topic: Java1.5语言新特性简单总结

1.Java1.5语言新特性简单总结

Posted by: java_china
Posted on: 2005-08-29 14:49

1. 自动装箱与拆箱对应C#
例1.1
Integer i = 10;
int j = i;

2. 更优化的for循环对应就C#---foreach循环
例2.1
String[] names = {"BadBoy","GoodBoy","HappyGirl","sadGirl"};
for(String option: names) {
System.out.println(option);
}
例2.2 加泛型对应C++模板
import java.util.*;

ArrayList<String> animals = new ArrayList<String>();
animals.add("Dog");
animals.add("Cat");
animals.add("Chick");
animals.add("Cow");
for(String option : animals) {
System.out.println(option);
}

3.参数可变的方法和printf
例3.1
定义:
public int sum(int... n) { //传过来n为一个int型数组
int tempSum;
for(int option : n) {
tempSum+=option;
}
/*
for(int i = 0; i < n.length; i++) {
tempSum+=n[i];
}
*/
return tempSum;
}
调用1: sum(1);
调用2: sum(1,2);
调用3: sum(1,2,3,4);
例3.2 printf方法, 对应c语言的printf
int x = 10;
int y = 20;
int sum = x + y;
System.out.printf("%d + %d = %d",x,y,sum);

4. 枚举
例4.1
public enum MyColors {
red,
black,
blue,
green,
yellow
}

MyColors color = MyColors.red;
for(MyColors option : color.values()) {
System.out.println(option);
}

/**不能在switch语句里这样写case MyColors.red:
*这样编译器不会让你通过*/
switch(color) {
case red:
System.out.println("best color is "+red);
break;
case black:
System.out.println("NO " + black);
break;
default:
System.out.println("What");
break;
}

5.静态引用
例5.1
1.5版本以前的写法是：

　　import java.lang.Math; //程序开头处

　　...

　　double x = Math.random();
1.5版本中可以这样写
import static java.lang.Math.random; //程序开头处

...
　　
double x = random();

希望各位有新的发现,可以跟进,多谢!

2.Re:Java1.5语言新特性简单总结 [Re: java_china]	Copy to clipboard
Posted by: hunterx Posted on: 2005-08-29 15:10 学习中，具体使用还要等一久。

3.Re:Java1.5语言新特性简单总结 [Re: java_china]	Copy to clipboard
Posted by: justforfun Posted on: 2005-08-29 20:20 java_china wrote: 希望各位有新的发现,可以跟进,多谢! You are a Thief!! Copied from http://www.javaresearch.org/article/showarticle.jsp?column=545&thread=32349

4.Re:Java1.5语言新特性简单总结 [Re: java_china]	Copy to clipboard
Posted by: uefs Posted on: 2008-01-30 14:46 这些简单的总结真得是没有用处，到处都是简单总结，好象java真得很简单一样

5.Re:Java1.5语言新特性简单总结 [Re: java_china]	Copy to clipboard
Posted by: JiafanZhou Posted on: 2008-01-30 16:56 I like it, always like the KISS law. Keep it simple and stupid.

6.Re:Java1.5语言新特性简单总结 [Re: java_china]

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Posted by: flytiger
Posted on: 2008-02-02 08:32

4. 枚举
例4.1
public enum MyColors {
red,
black,
blue,
green,
yellow
}

MyColors color = MyColors.red;
for(MyColors option : color.values()) {
System.out.println(option);
}

/**不能在switch语句里这样写case MyColors.red:
*这样编译器不会让你通过*/
switch(color) {
case red:
System.out.println("best color is "+red);
break;
case black:
System.out.println("NO " + black);
break;
default:
System.out.println("What");
break;
}

correction
4. 枚举
例4.1
public enum MyColors {
red,
black,
blue,
green,
yellow
}

MyColors color = MyColors.red;
for(MyColors option : MyColors.values()) {
System.out.println(option);
}

/**不能在switch语句里这样写case MyColors.red:
*这样编译器不会让你通过*/
switch(color) {
case red:
System.out.println("best color is "+MyColors.red);
break;
case black:
System.out.println("NO " + MyColors.black);
break;
default:
System.out.println("What");
break;
}