在做Java开发的时候，常常会出现一些乱码，或者无法正确识别或读取的文件，比如常见的validator验证用的消息资源（properties）文 件就需要进行Unicode重新编码。原因是java默认的编码方式为Unicode，而计算机系统编码常常是GBK等编码。需要将系统的编码转换 为java正确识别的编码问题就解决了。
native2ascii 工具将带有本机编码字符（非拉丁 1 和非单一码字符）的文件转换成带有Unicode编码字符的文件。
源文件：old.properties
key1=java無名
key2=博客
key3=测试
转换为Unicode编码，注意指定编码格式，测试也可以默认
native2ascii -encoding UTF-8 old.properties new.properties
native2ascii.exe是一个应用比较简单的转码工具，并且转码是可逆的。
将Unicode编码转为普通编码，注意-reverse参数
新文件：new.properties
native2ascii -reverse -encoding UTF-8 new.properties new2.properties
JDK自带的工具native2ascii可以将uncode编码的文件转换为本地编码的文件，但是不能批量转换文件。
Java代码中的使用，注意，如果你的命令行时没有加编码参数，那么在Eclipse里面使用的时候可能会出现乱码：
public class Native2AsciiUtils {
/**
* prefix of ascii string of native character
*/
private static String PREFIX = "\\u";
/**
* Native to ascii string. It's same as execut native2ascii.exe.
* @param str native string
* @return ascii string
*/
public static String native2Ascii(String str) {
char[] chars = str.toCharArray();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < chars.length; i++) {
sb.append(char2Ascii(chars[i]));
}
return sb.toString();
}
/**
* Native character to ascii string.
* @param c native character
* @return ascii string
*/
private static String char2Ascii(char c) {
if (c > 255) {
StringBuilder sb = new StringBuilder();
sb.append(PREFIX);
int code = (c >> 8);
String tmp = Integer.toHexString(code);
if (tmp.length() == 1) {
sb.append("0");
}
sb.append(tmp);
code = (c & 0xFF);
tmp = Integer.toHexString(code);
if (tmp.length() == 1) {
sb.append("0");
}
sb.append(tmp);
return sb.toString();
} else {
return Character.toString(c);
}
}
/**
* Ascii to native string. It's same as execut native2ascii.exe -reverse.
* @param str ascii string
* @return native string
*/
public static String ascii2Native(String str) {
StringBuilder sb = new StringBuilder();
int begin = 0;
int index = str.indexOf(PREFIX);
while (index != -1) {
sb.append(str.substring(begin, index));
sb.append(ascii2Char(str.substring(index, index + 6)));
begin = index + 6;
index = str.indexOf(PREFIX, begin);
}
sb.append(str.substring(begin));
return sb.toString();
}
/**
* Ascii to native character.
* @param str ascii string
* @return native character
*/
private static char ascii2Char(String str) {
if (str.length() != 6) {
throw new IllegalArgumentException("Ascii string of a native character must be 6 character.");
}
if (!PREFIX.equals(str.substring(0, 2))) {
throw new IllegalArgumentException("Ascii string of a native character must start with \"\\u\".");
}
String tmp = str.substring(2, 4);
int code = Integer.parseInt(tmp, 16) << 8;
tmp = str.substring(4, 6);
code += Integer.parseInt(tmp, 16);
return (char) code;
}
public static void main(String[] args) {
String uni = "java\u5c0f\u5f3a";
System.out.println(ascii2Native(uni));
}
}
运行效果如下：
