无法通过 System.in 读取日文字符

Question

Code:

Scanner sc = new Scanner(System.in);
System.out.println("Enter Name : ");
String name = sc.nextLine();
System.out.println(name);

String encoding = "UTF-8";
System.out.println(new String(name.getBytes(encoding), "euc-jp"));
System.out.println(new String(name.getBytes(encoding), "Shift_JIS"));
System.out.println(new String(name.getBytes(encoding), "ISO-2022-JP"));
System.out.println(new String(name.getBytes(encoding), "ISO8859-1"));

Input:

Enter Name : たなかです

Output:

F Q N @

鐃 鐃 鐃緒申鐃 鐃

ｿｽF ｿｽQ ｿｽ ｿｽ ｿｽN ｿｽ@

F Q N @

�F�Q���N�@

None of them are readable Japanese. I've also tried InputStreamReader and DataInputStream with Byte[] .

Answer 1

How to print the string properly to console with your code

name.getBytes(encoding) in your code will get the raw-byte representation of the String name with UTF-8 encoding. So when you type "たなかです" in console, you will get the array of byte {0xE3, 0x81, 0x9F, 0xE3, 0x81, 0xAA, 0xE3, 0x81, 0x8B, 0xE3, 0x81, 0xA7, 0xE3, 0x81, 0x99} .

It is UTF-8 based representation, so the only encoding you can specify in the 2nd argument of the constructor String(byte[] bytes, String charsetName) is UTF-8 .

System.out.println(new String(name.getBytes(encoding), "UTF-8"));

It converts the byte array {0xE3, 0x81, 0x9F, ... } to a String object, and prints to the console properly.

How to get the internal representation of a String as a byte array

String object uses UTF-16 for the internal text representation (see https://docs.oracle.com/javase/8/docs/technotes/guides/intl/overview.html for details).

So you have to use name.getBytes("UTF-16") when you want to get the byte array that same as the internal text representation. You can reverse it to a String object with System.out.println(new String(name.getBytes("UTF-16"), "UTF-16")); .

Answer 2

there is slight problem in your following code snippet, you are using same encoding for different charsets,

String encoding = System.getProperty("file.encoding"); 
System.out.println(new String(name.getBytes(encoding), "UTF-8"));

assuming you want to print the japanese characters using different charset's ,use this

 System.out.println(new String(name.getBytes("euc-jp"), "euc-jp"));
 System.out.println(new String(name.getBytes("Shift_JIS"), "Shift_JIS"));
 System.out.println(new String(name.getBytes("ISO-2022-JP"), "ISO-2022-JP"));
 System.out.println(new String(name.getBytes("ISO8859-1"), "ISO8859-1"));