在java中怎么对字符进行全角与半角的转换

public class AsciiUtil { public static final char SBC_SPACE = 12288; // 全角空格 12288 public static final char DBC_SPACE = 32; //半角空格 32 // ASCII character 33-126 <-> unicode 65281-65374 public static final char ASCII_START = 33; public static final char ASCII_END = 126; public static final char UNICODE_START = 65281; public static final char UNICODE_END = 65374; public static final char DBC_SBC_STEP = 65248; // 全角半角转换间隔 public static char sbc2dbc(char src){  if (src == SBC_SPACE) {   return DBC_SPACE;  }  if (src >= UNICODE_START && src <= UNICODE_END) {   return (char) (src - DBC_SBC_STEP);  }  return src; }  public static String sbc2dbcCase(String src) {  if (src == null) {   return null;  }  char[] c = src.toCharArray();  for (int i = 0; i < c.length; i++) {   c[i] = sbc2dbc(c[i]);  }  return new String(c); } public static char dbc2sbc(char src){  if (src == DBC_SPACE) {   return SBC_SPACE;  }  if (src <= ASCII_END) {   return (char) (src + DBC_SBC_STEP);  }  return src; }  public static String dbc2sbcCase(String src) {  if (src == null) {   return null;  }  char[] c = src.toCharArray();  for (int i = 0; i < c.length; i++) {   c[i] = dbc2sbc(c[i]);  }  return new String(c); }}