Java 中创建字符串对象的常见方式: 

/* 
*              1. 空参构造 such : String s1 = new String();
*              2. 创建字符串对象，传入字符串对象 such : String s2 = new String(String s);
*              3. 创建字符串对象，传入字符串 such : String s3 = new String("abc");
*              4. 传入字节数组 such : String s4 = new String(byte[] bytes);
*              5. 传入字节数组的 起始索引，所需长度 
*              such : String s5 = new String(byte[] bytes, int start, int length);
*              6. 传入字符数组 such : String s6 = new String(char[] chars);
*              7. 传入字符数组的 起始索引，所需长度
*              such : String s7 = new String(char[] chars, int start, int length);
*
*/

String s1 = new String();
String str = "abc";
String s2 = new String(str);
String s3 = new String("ABC");
byte[] bytes = {97, 98, 99, 100, 101, 102};
String s4 = new String(bytes);
String s5 = new String(bytes,2,3);
char[] chars = {'A','B','C','D','E','F'};
String s6 = new String(chars);
String s7 = new String(chars,1,3);

// print：

System.out.println(s1);
System.out.println(s2);
System.out.println(s3);
System.out.println(s4);
System.out.println(s5);
System.out.println(s6);
System.out.println(s7);

// result:

abc
ABC
abcdef
cde
ABCDEF
BCD