Java全角和半角的轉換代碼 
public class change { 

public static void main(String[] args) { 

String QJstr="全角轉半角ＤＡＯ"; 

String result=SBCchange(QJstr); 

System.out.println(QJstr+"\n"+result); 

} 

public static final String SBCchange(String QJstr) 
{ 
String outStr=""; 
String Tstr=""; 
byte[] b=null; 

for(int i=0;i<QJstr.length();i++) 
{ 
try 
{ 
Tstr=QJstr.substring(i,i+1); 
b=Tstr.getBytes("unicode"); 
} 
catch(java.io.UnsupportedEncodingException e) 
{ 
e.printStackTrace(); 
} 

if (b[3]==-1) 
{ 
b[2]=(byte)(b[2]+32); 
b[3]=0; 

try 
{ 
outStr=outStr+new String(b,"unicode"); 
} 
catch(java.io.UnsupportedEncodingException e) 
{ 
e.printStackTrace(); 
} 
}else outStr=outStr+Tstr; 
} 

return outStr; 
} 

} 







public class Test { 
public static void main(String[] args) { 
String QJstr = "hello"; 
String QJstr1 = "ｈｅｈｅ"; 

String result = BQchange(QJstr); 
String result1 = QBchange(QJstr1); 

System.out.println(QJstr + "\n" + result); 
System.out.println(QJstr1 + "\n" + result1); 
} 

// 半角轉全角 
public static final String BQchange(String QJstr) { 
String outStr = ""; 
String Tstr = ""; 
byte[] b = null; 

for (int i = 0; i< QJstr.length(); i++) { 
try { 
Tstr = QJstr.substring(i, i + 1); 
b = Tstr.getBytes("unicode"); 
} catch (java.io.UnsupportedEncodingException e) { 
e.printStackTrace(); 
} 
if (b[3] != -1) { 
b[2] = (byte) (b[2] - 32); 
b[3] = -1; 
try { 
outStr = outStr + new String(b, "unicode"); 
} catch (java.io.UnsupportedEncodingException e) { 
e.printStackTrace(); 
} 
} else 
outStr = outStr + Tstr; 
} 
return outStr; 
} 

// 全角轉半角 
public static final String QBchange(String QJstr) { 
String outStr = ""; 
String Tstr = ""; 
byte[] b = null; 

for (int i = 0; i< QJstr.length(); i++) { 
try { 
Tstr = QJstr.substring(i, i + 1); 
b = Tstr.getBytes("unicode"); 
} catch (java.io.UnsupportedEncodingException e) { 
e.printStackTrace(); 
} 
if (b[3] == -1) { 
b[2] = (byte) (b[2] + 32); 
b[3] = 0; 
try { 
outStr = outStr + new String(b, "unicode"); 
} catch (java.io.UnsupportedEncodingException e) { 
e.printStackTrace(); 
} 
} else 
outStr = outStr + Tstr; 
} 
return outStr; 
} 
} 



/**/// / 
// / 轉全角的函數(SBC case) 
// / 
// /任意字符串 
// /全角字符串 
// / 
// /全角空格為12288，半角空格為32 
// /其他字符半角(33-126)與全角(65281-65374)的對應關系是：均相差65248 
// / 
public static String ToSBC(String input) { 
// 半角轉全角： 
char[] c = input.toCharArray(); 
for (int i = 0; i< c.length; i++) { 
if (c[i] == 32) { 
c[i] = (char) 12288; 
continue; 
} 
if (c[i]< 127) 
c[i] = (char) (c[i] + 65248); 
} 
return new String(c); 
} 

/**/// / 
// / 轉半角的函數(DBC case) 
// / 
// /任意字符串 
// /半角字符串 
// / 
// /全角空格為12288，半角空格為32 
// /其他字符半角(33-126)與全角(65281-65374)的對應關系是：均相差65248 
// / 
public static String ToDBC(String input) { 
char[] c = input.toCharArray(); 
for (int i = 0; i< c.length; i++) { 
if (c[i] == 12288) { 
c[i] = (char) 32; 
continue; 
} 
if (c[i]> 65280&& c[i]< 65375) 
c[i] = (char) (c[i] - 65248); 
} 
return new String(c); 
}