java 全角和半角的转换

版本1：
public class change {
   
     public static void main(String[] args) {
   
      String QJstr="全角转半角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;
   }

}

版本2
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);
}

// 半角转全角
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;
}

// 全角转半角
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;
}
}

/**/// /
// / 转全角的函数(SBC case)
// /
// / 任意字符串
// /全角字符串
// /
// /全角空格为12288，半角空格为32
// /其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
// /
public static String ToSBC(String input) {
// 半角转全角：
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);
}

/**/// /
// / 转半角的函数(DBC case)
// /
// / 任意字符串
// /半角字符串
// /
// /全角空格为12288，半角空格为32
// /其他字符半角(33-126)与全角(65281-65374)的对应关系是：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);
}