1、while循環

public class Test {   public static void main(String args[]) {      int x = 10;      while( x < 20 ) {         System.out.PRint("value of x : " + x );         x++;         System.out.print("");      }   }}2、do  while
public class Test {   public static void main(String args[]){      int x = 10;      do{         System.out.print("value of x : " + x );         x++;         System.out.print("");      }while( x < 20 );   }}3、for
public class Test {   public static void main(String args[]) {      for(int x = 10; x < 20; x = x+1) {         System.out.print("value of x : " + x );         System.out.print("");      }   }}
public class Test {   public static void main(String args[]){      int [] numbers = {10, 20, 30, 40, 50};      for(int x : numbers ){         System.out.print( x );         System.out.print(",");      }      System.out.print("");      String [] names ={"James", "Larry", "Tom", "Lacy"};      for( String name : names ) {         System.out.print( name );         System.out.print(",");      }   }}
遍歷List集合的三種方法
List<String> list = new ArrayList<String>();list.add("aaa");list.add("bbb");list.add("ccc");方法一：超級for循環遍歷for(String attribute : list) {  System.out.println(attribute);}方法二：對于ArrayList來說速度比較快, 用for循環, 以size為條件遍歷:for(int i = 0 ; i < list.size() ; i++) {  system.out.println(list.get(i));}方法三：集合類的通用遍歷方式, 從很早的版本就有, 用迭代器迭代Iterator it = list.iterator();while(it.hasNext()) {  System.ou.println(it.next);}