java求快

字符串操作而已，看看String里面的方法吧。

package test;

public class StringTest {
    public static void main(String[] args) {
        String temp;
        String str="good morning";
        System.out.println("原：" +str);
        str=str.replace('o','w');
        System.out.println("o全换成w后:" +str);
        temp=str;
        str="";
        for(int i=0;i<temp.length();i++){
            if(temp.charAt(i)!='n'){
                str+=temp.charAt(i);
            }
        }
        System.out.println("去掉所有n后:"+str);
        str=str.replace("g","12345g");
        System.out.println("在g前面加12345后:"+str);
        System.out.println("字符串长度为:"+str.length());
        str=str.toUpperCase();
        System.out.println("字符串小写变为大写后:"+str);
        temp=str;
        str="";
        for(int i=temp.length()-1;i>=0;i--){
            str+=temp.charAt(i);
        }
        System.out.println("字符串倒序输出:" +str);
    }
}