輸出數值 123456789.234, 會得到 1.23456789234E8,
這時候, 可以利用『java.text.DecimalFormat』類別的『applyPattern』與『format』方法, 設定數值資料的格式化.
參考範例, 如下 :
程式碼
public class HelloTomKuoWorld
{
public static void main( String args[] )
{
double d1 = 123456789.234, d2 = 123456789.235, d3 = 123;
DecimalFormat df = new DecimalFormat();
System.out.println( "=== No Format ===" );
System.out.println( "d1 = " + d1 ); // 1.23456789234E8
System.out.println( "d2 = " + d2 ); // 1.23456789235E8
System.out.println( "d3 = " + d3 ); // 123.0
df.applyPattern( "0" );
System.out.println( "=== 0 ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123456789
System.out.println( "d2 = " + df.format(d2) ); // 123456789
System.out.println( "d3 = " + df.format(d3) ); // 123
df.applyPattern( "0.00" );
System.out.println( "=== 0.00 ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123456789.23
System.out.println( "d2 = " + df.format(d2) ); // 123456789.24
System.out.println( "d3 = " + df.format(d3) ); // 123.00
df.applyPattern( "0,000.00" );
System.out.println( "=== 0,000.00 ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123,456,789.23
System.out.println( "d2 = " + df.format(d2) ); // 123,456,789.24
System.out.println( "d3 = " + df.format(d3) ); // 0,123.00
df.applyPattern( "$0,000.00" );
System.out.println( "=== $0,000.00 ===" );
System.out.println( "d1 = " + df.format(d1) ); // $123,456,789.23
System.out.println( "d2 = " + df.format(d2) ); // $123,456,789.24
System.out.println( "d3 = " + df.format(d3) ); // $0,123.00
df.applyPattern( "#" );
System.out.println( "=== # ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123456789
System.out.println( "d2 = " + df.format(d2) ); // 123456789
System.out.println( "d3 = " + df.format(d3) ); // 123
df.applyPattern( "#.##" );
System.out.println( "=== #.## (Recommand) ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123456789.23
System.out.println( "d2 = " + df.format(d2) ); // 123456789.24
System.out.println( "d3 = " + df.format(d3) ); // 123
df.applyPattern( "#,###.##" );
System.out.println( "=== #,###.## ===" );
System.out.println( "d1 = " + df.format(d1) ); // 123,456,789.23
System.out.println( "d2 = " + df.format(d2) ); // 123,456,789.24
System.out.println( "d3 = " + df.format(d3) ); // 123
}
}