String str0 = "最正常的创建方法";

        System.out.println(str0);

        char[] c1 = new char[3];

        c1[0] = 'c';

        c1[1] = 'b';

        c1[2] = 'a';

        String str1 =new String("string1");

        String str2 = new String(c1);

        System.out.println(str1+ " "+ str2); //输出string1 cba

        /* String.valueOf()它可以将JAVA基本类型(int,double,boolean等)和对象(Object)转换成String型

         * toString()是对象的方法，它可以将该对象转换成String型，转换算法根据类型实际需要而定，

         * 基本上JAVA里面每个对象都会有一个toString方法。*/

        //字符串转换

        int i1 = 100;

        String str3= Integer.toString(i1);

        System.out.println("Integer.toString : "+str3);//输出Integer.toString : 100

        //valueOf()进行数据转换

        String str32  = String.valueOf(123456);

        System.out.println("String.valueOf() : " +str32);//输出String.valueOf() : 123456

        //字符抽取

        //charAt

        String str4 = "A long String!";

        System.out.println("charAt(3) : "+str4.charAt(3));//输出charAt(3) : o

        //getChars()

        char buf [] = new char[6-2];

        str4.getChars(2, 6, buf    , 0);

        System.out.print("getChars输出 ：");

        System.out.println(buf); //输出getChars输出 ：long

        //char[] toCharArray()

        System.out.println(str4.toCharArray());//输出A long String!

        //抽取子串

        String str5 = str4.substring(2,8);

        System.out.println("subString(2,8)输出 : "+str5);//输出subString(2,8)输出 : long S
    

        /*

         * StringBuffer()

         * StringBuffer(int size)

         * StringBuffer(String str)

         * 接收一个String变元，指定StringBuffer对象的初始内容，并额外预留16个字符空间

         * StringBuffer(CharSequence chars)

         */

        StringBuffer sbf = new StringBuffer("Hello");

        System.out.println("buffer = " +sbf);

        System.out.println("length = " +sbf.length());

        System.out.println("capacity = " +sbf.capacity());

        System.out.println("----重新指定缓冲区大小----");

        sbf.ensureCapacity(55);

        System.out.println("buffer = " +sbf);

        System.out.println("length = " +sbf.length());

        System.out.println("capacity = " +sbf.capacity());

        System.out.println("----设置缓冲区长度----");

        sbf.setLength(30);

        System.out.println("buffer = " +sbf);

        System.out.println("length = " +sbf.length());

        System.out.println("capacity = " +sbf.capacity());
        

buffer = Hello

length = 5

capacity = 21

----重新指定缓冲区大小----

buffer = Hello

length = 5

capacity = 55

----设置缓冲区长度----

buffer = Hello
length = 30
capacity = 55