Java中汉字、字母、数字所占字节是多少？

1.重点：

不同的编码格式占字节数是不同的，UTF-8编码下一个中文所占字节也是不确定的，可能是2个、3个、4个字节；

2.不多说，直接上程序：

@Test
    public void test1() throws UnsupportedEncodingException {
        String a = "名";
        System.out.println("UTF-8编码长度:"+a.getBytes("UTF-8").length);
        System.out.println("GBK编码长度:"+a.getBytes("GBK").length);
        System.out.println("GB2312编码长度:"+a.getBytes("GB2312").length);
        System.out.println("==========================================");
        String c = "0x20001";
        System.out.println("UTF-8编码长度:"+c.getBytes("UTF-8").length);
        System.out.println("GBK编码长度:"+c.getBytes("GBK").length);
        System.out.println("GB2312编码长度:"+c.getBytes("GB2312").length);
        System.out.println("==========================================");
        char[] arr = Character.toChars(0x20001);
        String s = new String(arr);
        System.out.println("char array length:" + arr.length);
        System.out.println("content:|  " + s + " |");
        System.out.println("String length:" + s.length());
        System.out.println("UTF-8编码长度:"+s.getBytes("UTF-8").length);
        System.out.println("GBK编码长度:"+s.getBytes("GBK").length);
        System.out.println("GB2312编码长度:"+s.getBytes("GB2312").length);
        System.out.println("==========================================");
    }

3.结果：

UTF-8编码长度:3
GBK编码长度:2
GB2312编码长度:2
==========================================
UTF-8编码长度:7
GBK编码长度:7
GB2312编码长度:7
==========================================
char array length:2
content:|  ? |
String length:2
UTF-8编码长度:4
GBK编码长度:1
GB2312编码长度:1
==========================================