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 } }