Java图表类库使用介绍：jCharts
jopen
10年前
jCharts是一款基于Java的图表绘制类库，jCharts包含了多种图表格式，包括线型图、饼图、柱形图和点图等。
jCharts的特点
- 100%基于Java，继承其跨平台的特性。
- 图表中的文字，包括x轴和y轴上的文字，均可以设置字体。
- 图表数据构造非常简单。
jCharts使用案例
柱形图绘制
完整的Java代码：
package com.jiuxing.mobile; import java.awt.Color; import java.awt.Font; import java.awt.Paint; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.krysalis.jcharts.axisChart.AxisChart; import org.krysalis.jcharts.axisChart.customRenderers.axisValue.renderers.ValueLabelPosition; import org.krysalis.jcharts.axisChart.customRenderers.axisValue.renderers.ValueLabelRenderer; import org.krysalis.jcharts.chartData.AxisChartDataSet; import org.krysalis.jcharts.chartData.DataSeries; import org.krysalis.jcharts.chartData.interfaces.IAxisDataSeries; import org.krysalis.jcharts.encoders.ServletEncoderHelper; import org.krysalis.jcharts.properties.AxisProperties; import org.krysalis.jcharts.properties.BarChartProperties; import org.krysalis.jcharts.properties.ChartProperties; import org.krysalis.jcharts.properties.DataAxisProperties; import org.krysalis.jcharts.properties.LegendProperties; import org.krysalis.jcharts.properties.PropertyException; import org.krysalis.jcharts.properties.util.ChartFont; import org.krysalis.jcharts.types.ChartType; public class BarChartServlet extends HttpServlet { // ---all of my charts serviced by this Servlet will have the same properties. private BarChartProperties barChartProperties; // ---all of my charts serviced by this Servlet will have the same properties. protected LegendProperties legendProperties; protected AxisProperties axisProperties; protected ChartProperties chartProperties; protected int width = 950; protected int height = 360; /********************************************************************************************** * **********************************************************************************************/ public void init() { this.legendProperties = new LegendProperties(); this.chartProperties = new ChartProperties(); // 图形的XY轴的属性对象 this.axisProperties = new AxisProperties(false); // 图表横坐标和纵坐标范围的字体，大小，颜色设置对象 ChartFont axisScaleFont = new ChartFont(new Font( "Georgia Negreta cursiva", Font.PLAIN, 13), new Color(18, 189, 255)); axisProperties.getXAxisProperties().setScaleChartFont(axisScaleFont); axisProperties.getYAxisProperties().setScaleChartFont(axisScaleFont); // Bar图形的横坐标和纵坐标的标题字体和颜色 ,大小的设置对象 ChartFont axisTitleFont = new ChartFont(new Font("Arial Narrow", Font.PLAIN, 14), new Color(18, 189, 255)); axisProperties.getXAxisProperties().setTitleChartFont(axisTitleFont); axisProperties.getXAxisProperties().setShowEndBorder(false); axisProperties.getYAxisProperties().setTitleChartFont(axisTitleFont); axisProperties.getYAxisProperties().setShowEndBorder(false); DataAxisProperties dataAxisProperties = (DataAxisProperties) axisProperties .getYAxisProperties(); try { // 设置用户定义的纵轴纵坐标的 间隔范围 dataAxisProperties.setUserDefinedScale(0, 3000); } catch (PropertyException propertyException) { propertyException.printStackTrace(); } dataAxisProperties.setRoundToNearest(3); // 设置图形标题的字体，颜色，大小 ChartFont titleFont = new ChartFont(new Font("Georgia Negreta cursiva", Font.PLAIN, 14), new Color(18, 189, 255)); // 生成图像的属性对象 this.chartProperties.setTitleFont(titleFont); // Bar图形的属性类 this.barChartProperties = new BarChartProperties(); ValueLabelRenderer valueLabelRenderer = new ValueLabelRenderer(false, false, true, -1); valueLabelRenderer.setValueLabelPosition(ValueLabelPosition.ON_TOP); // 是否设置显示的纵坐标标签垂直，true为是，flase为水平 valueLabelRenderer.useVerticalLabels(true); barChartProperties.addPostRenderEventListener(valueLabelRenderer); } /********************************************************************************************** * **********************************************************************************************/ public void service(HttpServletRequest req, HttpServletResponse httpServletResponse) throws ServletException, IOException { try { // 设置横坐标标签 String[] xAxisLabels = { "1995", "1996", "1997", "1998", "1999", "2000", "2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010", "2011", "2012", "2013", "2014" }; // 设置横坐标的单位 String xAxisTitle = "Years"; // 设置纵坐标的标题 String yAxisTitle = "Problems"; // 设置图形的标题 String title = "Micro$oft At Work"; // 图形所需要的数据对象 IAxisDataSeries dataSeries = new DataSeries(xAxisLabels, xAxisTitle, yAxisTitle, title); // 设置条形数据 double[][] data = new double[][] { { 1500, 6880, 4510, 2600, 0, 1580, 0, 9555, 11000, 0, 7500, 5880, 3510, 2600, 1200, 1580, 9000, 8555, 9000, 3120 } }; // 条形区域 形示的标签 String[] legendLabels = { "8" }; // String[] legendLabels = null; // 条形区域绘制的颜色设置对象 Paint[] paints = new Paint[] { new Color(18, 189, 255) }; dataSeries.addIAxisPlotDataSet(new AxisChartDataSet(data, legendLabels, paints, ChartType.BAR, this.barChartProperties)); // 产生一个 chart对象 AxisChart axisChart = new AxisChart(dataSeries, this.chartProperties, this.axisProperties, this.legendProperties, this.width, this.height); // 输出设置好的chart图形 ServletEncoderHelper.encodeJPEG13(axisChart, 1.0f, httpServletResponse); } catch (Throwable throwable) { // HACK do your error handling here... throwable.printStackTrace(); } } } 效果图如下：
总体来说，jCharts可以完成基本的图表绘制，并可以自己扩展代码来完成更高级的图表和报表功能。
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