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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本文作者：码农网 – 小峰