public class Test {

	public static void main(String[] args) {

	    /*

	     * int类型转String类型

	     */

	    int n1 = 9;

	    //1.采用String类的valueOf方法

	    String s1=String.valueOf(n1);

	    //2.采用+""的形式

	    String s2= n1+"";

	    //3.Integer的toString方法

	    String s3= Integer.toString(n1);

	    System.out.println("Number "+n1+" to String is:"+s1);

	    System.out.println("Number "+n1+" to String is:"+s2);

	    System.out.println("Number "+n1+" to String is:"+s3);

	    /*

	     * String类型转int类型

	     */

	    String s="123";

	    int i = Integer.parseInt( s );

	    System.out.println("String "+s+" to number is:"+i);

	}

}

Number  to String is:

Number  to String is:

Number  to String is:

String  to number is: