CategoryPlot categoryplot = (CategoryPlot)chart.getPlot(); 

       NumberAxis numberaxis = (NumberAxis)categoryplot.getRangeAxis(); 

        decimalFormat = new DecimalFormat("格式");         

         numberaxis.setNumberFormatOverride(decimalFormat);

//格式將指定縱坐標的顯示格式,可以顯示整數(shù),小數(shù),百分比等

比如:

0.00  顯示如:56.89

0.00%  顯示如:56.89%

0  顯示如57

0% 顯示如57%