javaAPI（1）之String類的常見操作

簡單使用：

public class APITest {
    public static void main(String[] args){
        String name="Machin.echjidhu ";
        System.out.println("字符串的長度爲："+name.length());
        System.out.println("字符串是否爲空："+name.isEmpty());
        System.out.println("下標爲5的字符是："+name.charAt(5));
        System.out.println("字符串是否爲          \"Machine\":"+name.equals("Machine"));
        System.out.println("c字符第一次出現的下標是："+name.indexOf('c'));
        System.out.println("c字符第一次出現的下標是："+name.lastIndexOf('c'));
        System.out.println("字符串是否以\"Mac\"開頭"+name.startsWith("Mac"));
        System.out.println("字符串是否爲hu結束"+name.endsWith("hu"));
        System.out.println("字符是否包含:"+name.contains("ech"));
        System.out.println("將字符串變成大寫："+name.toUpperCase());
        System.out.println("將字符串變成小寫："+name.toLowerCase());
        System.out.println("返回一個字符串："+String.valueOf(89));
        char[] oe = name.toCharArray();
        System.out.print("字符串轉化爲字符數組後爲：");
        for(int i=0;i<name.length();i++){
            if(i!=name.length()-1){
                System.out.print(oe[i]+",");
            }
            else{
                System.out.print(oe[i]+"\n");
            }
        }
        System.out.println("字符串中的ine用eni代替:"+name.replace("ine", "eni"));
        String[] a=name.split("\\.");
        System.out.println("字符串分割成.左右的字符串："+a[0]+","+a[1]);
        System.out.println("返回下標值4及後面的字符串"+name.substring(4));
        System.out.println("返回下標值4後面(包括4)9前面(不包括9)的字符串"+name.substring(4,9));
        System.out.println("去除首尾空格的字符串:"+name.trim());

    }
}