java中各種資料類型佔用位元組數

標籤：

1位元組(Byte)=8bit

java的基本類型

類型	所佔位元組
byte	1
short	2
int	4
long	8
float	4
double	8
char	2

 

 

 

 

 

 

String中字母和漢字所佔字元是不一樣的，並且與編碼有關

英文字母：A

位元組數	編碼
1	GB2312
1	GBK
1	GB18030
1	ISO-8859-1
1	UTF-8
4	UTF-16
2	UTF-16BE
2	UTF-16-LE

 

 

 

 

 

 

 

中文漢字：我

位元組數	編碼
1	GB2312
2	GBK
2	GB18030
1	ISO-8859-1
3	UTF-8
4	UTF-16
2	UTF-16BE
2	UTF-16-LE

 

 

 

 

 

 

 

附錄：計算String位元組數的代碼

package com.dingrui.stringbytelength;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import org.dozer.loader.api.FieldDefinition;public class StringByteLength {/* * GB2312 GBK GB18030 ISO-8859-1 UTF-8 UTF-16 UTF-16BE UTF-16LE */public static void main(String[] args) throws IOException {String s1 = "a";String s2 = "龘";System.out.println(s1 + "  GB2312  " + s1.getBytes("GB2312").length);System.out.println(s1 + "  GBK  " + s1.getBytes("GBK").length);System.out.println(s1 + "  GB18030  " + s1.getBytes("GB18030").length);System.out.println(s1 + "  ISO-8859-1  " + s1.getBytes("ISO-8859-1").length);System.out.println(s1 + "  UTF-8  " + s1.getBytes("UTF-8").length);System.out.println(s1 + "  UTF-16  " + s1.getBytes("UTF-16").length);System.out.println(s1 + "  UTF-16BE  " + s1.getBytes("UTF-16BE").length);System.out.println(s1 + "  UTF-16LE  " + s1.getBytes("UTF-16LE").length);System.out.println("---------------");System.out.println(s2 + "  GB2312  " + s2.getBytes("GB2312").length);System.out.println(s2 + "  GBK  " + s2.getBytes("GBK").length);System.out.println(s2 + "  GB18030  " + s2.getBytes("GB18030").length);System.out.println(s2 + "  ISO-8859-1  " + s2.getBytes("ISO-8859-1").length);System.out.println(s2 + "  UTF-8  " + s2.getBytes("UTF-8").length);System.out.println(s2 + "  UTF-16  " + s2.getBytes("UTF-16").length);System.out.println(s2 + "  UTF-16BE  " + s2.getBytes("UTF-16BE").length);System.out.println(s2 + "  UTF-16LE  " + s2.getBytes("UTF-16LE").length);}/** * 將轉碼後的文字寫入檔案，通過編輯器開啟測試，確認寫入的是相應編碼 *  * @param bytes * @throws IOException */public void writeFile(byte[] bytes) throws IOException {String path = StringByteLength.class.getResource("/").getPath();System.out.println(path);String file_path = path + "charsetFile";File file = new File(file_path);if (!file.exists()) {file.createNewFile();}FileOutputStream out = new FileOutputStream(file);out.write(bytes);out.close();}}

　　

 

java中各種資料類型佔用位元組數