java.text.DecimalFormat#setPositivePrefix ( )源码实例Demo

public static <T extends Number> byte[] convertSignedNumericToArray(int length, T value, int precision )
{

       // Pattern for fractional part
	char[] arrFractional = new char[precision];
	Arrays.fill(arrFractional, '0');

	// Pattern for mantissa
	char[] arrMantissa = new char[length - 1 - precision ];
	Arrays.fill(arrMantissa, '0');

	String patternDesired = String.format( "%s.%s", new String(arrMantissa), new String(arrFractional));
	DecimalFormat formatter = new DecimalFormat(patternDesired );
	formatter.setPositivePrefix("+");
	formatter.setNegativePrefix("-");
	formatter.setGroupingUsed(false);
	String formattedValue = formatter.format(value);
	DecimalFormatSymbols decimalFormatSymbol = formatter.getDecimalFormatSymbols();
	formattedValue = formattedValue.replace(String.valueOf(decimalFormatSymbol.getDecimalSeparator()), "");
       return formattedValue.getBytes(charsetISO_8859);
}
 

public static <T extends Number> byte[] convertUnsignedNumericToArray(int length, T value, int precision )
{

       // Pattern for fractional part
	char[] arrFractional = new char[precision];
	Arrays.fill(arrFractional, '0');

	// Pattern for mantissa
	char[] arrMantissa = new char[length - precision ];
	Arrays.fill(arrMantissa, '0');

	String patternDesired = String.format( "%s.%s", new String(arrMantissa), new String(arrFractional));
	DecimalFormat formatter = new DecimalFormat(patternDesired );
	formatter.setPositivePrefix("");
	formatter.setNegativePrefix("");
	formatter.setGroupingUsed(false);
	String formattedValue = formatter.format(value);
	DecimalFormatSymbols decimalFormatSymbol = formatter.getDecimalFormatSymbols();
	formattedValue = formattedValue.replace(String.valueOf(decimalFormatSymbol.getDecimalSeparator()), "");
       return formattedValue.getBytes(charsetISO_8859);
}
 

public FloatingPointFormat( int w, int d ) {
  width = w;
  decimal = d;
  nf = new DecimalFormat( pattern(w, d) );
  nf.setPositivePrefix(" ");
  nf.setNegativePrefix("-");
}
 

public ExponentialFormat( int digits, int exp, boolean sign, 
	    boolean trailing ) {
  this.digits = digits;
  this.exp = exp;
  this.sign = sign;
  this.trailing = trailing;
  nf = new DecimalFormat( pattern() );
  nf.setPositivePrefix("+");
  nf.setNegativePrefix("-");
}
 

/**
   * Constructor. Creates a FloatingPointFormat with the given values width and decimal size.
   * @param w width given.
   * @param d decimal size given.
   */
  public FloatingPointFormat( int w, int d ) {
  width = w;
  decimal = d;
  nf = new DecimalFormat( pattern(w, d) );
  nf.setPositivePrefix(" ");
  nf.setNegativePrefix("-");
}
 

/**
   ** Constructor. Creates a ExponentialFormat with the given arguments.
   * @param digits given base size.
   * @param exp given exponent size.
   * @param sign given sign flag.
   * @param trailing given trailing flag.
   */
  public ExponentialFormat( int digits, int exp, boolean sign, 
	    boolean trailing ) {
  this.digits = digits;
  this.exp = exp;
  this.sign = sign;
  this.trailing = trailing;
  nf = new DecimalFormat( pattern() );
  nf.setPositivePrefix("+");
  nf.setNegativePrefix("-");
}
 

/**
 * Return a matrix as a String.
 *
 * @return
 */
@Override
public synchronized String toString() {
    if ((rows <= 0) || (columns <= 0)) {
        return "[]";
    }
    int i, j;
    DecimalFormat format = new DecimalFormat("00.0000");
    format.setPositivePrefix("+");

    StringBuilder str = new StringBuilder();
    for (i = 0; i < (rows - 1); i++) {
        for (j = 0; j < (columns - 1); j++) {
            if (round(matrix[i][j] * 10000) != 0) {
                str.append(format.format(matrix[i][j])).append(" ");
            } else {
                str.append("-------- ");
            }
        }
        if (round(matrix[i][columns - 1] * 10000) != 0) {
            str.append(format.format(matrix[i][columns - 1])).append(NEW_LINE);
        } else {
            str.append("--------").append(NEW_LINE);
        }
    }
    for (j = 0; j < (columns - 1); j++) {
        if (round(matrix[rows - 1][j] * 10000) != 0) {
            str.append(format.format(matrix[rows - 1][j])).append(" ");
        } else {
            str.append("-------- ");
        }
    }
    if (round(matrix[rows - 1][columns - 1] * 10000) != 0) {
        str.append(format.format(matrix[rows - 1][columns - 1]));
    } else {
        str.append("-------- ");
    }
    return str.toString();
}
 

public void test_setPositivePrefix() throws Exception {
    DecimalFormat format = new DecimalFormat();
    assertEquals("", format.getPositivePrefix());

    format.setPositivePrefix("PosPrf");
    assertEquals("PosPrf", format.getPositivePrefix());
    assertTrue(format.parse("PosPrf123.45").doubleValue() == 123.45);

    format.setPositivePrefix("");
    assertEquals("", format.getPositivePrefix());

    format.setPositivePrefix(null);
    assertNull(format.getPositivePrefix());
}
 

public void test_getPositivePrefix() {
    DecimalFormat df = new DecimalFormat();
    df.setPositivePrefix("++");
    assertTrue("Incorrect positive prefix", df.getPositivePrefix().equals("++"));
}