怎么用java的相关类去画一个柱状图

可以使用java第三方JFreeChart的api：具体

import java.awt.Color

import java.awt.GradientPaint

import org.jfree.chart.ChartFactory

import org.jfree.chart.JFreeChart

import org.jfree.chart.axis.CategoryAxis

import org.jfree.chart.axis.CategoryLabelPositions

import org.jfree.chart.axis.NumberAxis

import org.jfree.chart.plot.CategoryPlot

import org.jfree.chart.plot.PlotOrientation

import org.jfree.chart.renderer.category.BarRenderer

import org.jfree.chart.renderer.category.BarRenderer3D

import org.jfree.data.category.CategoryDataset

import org.jfree.data.category.DefaultCategoryDataset

import org.jfree.data.general.DatasetUtilities

/**

* 柱状图测试

* @author xjh

*

*/

public class BarChartTest {

/**

* 得到2D柱状图的数据集合

*

* @return

*/

private CategoryDataset getDataset2D() {

String str1 = "First"

String str2 = "Second"

String str3 = "Third"

String str4 = "Category 1"

String str5 = "Category 2"

String str6 = "Category 3"

String str7 = "Category 4"

String str8 = "Category 5"

DefaultCategoryDataset localDefaultCategoryDataset = new DefaultCategoryDataset()

localDefaultCategoryDataset.addValue(1.0D, str1, str4)

localDefaultCategoryDataset.addValue(4.0D, str1, str5)

localDefaultCategoryDataset.addValue(3.0D, str1, str6)

localDefaultCategoryDataset.addValue(5.0D, str1, str7)

localDefaultCategoryDataset.addValue(5.0D, str1, str8)

localDefaultCategoryDataset.addValue(5.0D, str2, str4)

localDefaultCategoryDataset.addValue(7.0D, str2, str5)

localDefaultCategoryDataset.addValue(6.0D, str2, str6)

localDefaultCategoryDataset.addValue(8.0D, str2, str7)

localDefaultCategoryDataset.addValue(4.0D, str2, str8)

localDefaultCategoryDataset.addValue(4.0D, str3, str4)

localDefaultCategoryDataset.addValue(3.0D, str3, str5)

localDefaultCategoryDataset.addValue(2.0D, str3, str6)

localDefaultCategoryDataset.addValue(3.0D, str3, str7)

localDefaultCategoryDataset.addValue(6.0D, str3, str8)

return localDefaultCategoryDataset

}

/**

* 创建2D柱状图

*

* @param paramCategoryDataset

* @return

*/

public JFreeChart createBarChart2D() {

//得到2D柱状图的数据集合

CategoryDataset paramCategoryDataset = getDataset2D()

//创建柱状图

JFreeChart localJFreeChart = ChartFactory.createBarChart(

"Bar Chart Demo", "Category", "Value", paramCategoryDataset,

PlotOrientation.VERTICAL, true, true, false)

//设置柱状图属性

localJFreeChart.setBackgroundPaint(Color.white)

//获取柱状图的标注点集合

CategoryPlot localCategoryPlot = localJFreeChart.getCategoryPlot()

//设置标注点的背景色

localCategoryPlot.setBackgroundPaint(Color.lightGray)

//设置绘制区域的方格线的颜色

localCategoryPlot.setDomainGridlinePaint(Color.white)

//是方格线可见

localCategoryPlot.setDomainGridlinesVisible(true)

//设置方格线变动绘制颜色

localCategoryPlot.setRangeGridlinePaint(Color.white)

//得到数值坐标轴

NumberAxis localNumberAxis = (NumberAxis) localCategoryPlot

.getRangeAxis()

//设置坐标轴单元

localNumberAxis.setStandardTickUnits(NumberAxis

.createIntegerTickUnits())

//得到柱状图渲染器

BarRenderer localBarRenderer = (BarRenderer) localCategoryPlot

.getRenderer()

//如果超出绘制区域边界将不可见

localBarRenderer.setDrawBarOutline(false)

//创建倾斜度对象

GradientPaint localGradientPaint1 = new GradientPaint(0.0F, 0.0F,

Color.blue, 0.0F, 0.0F, new Color(0, 0, 64))

GradientPaint localGradientPaint2 = new GradientPaint(0.0F, 0.0F,

Color.green, 0.0F, 0.0F, new Color(0, 64, 0))

GradientPaint localGradientPaint3 = new GradientPaint(0.0F, 0.0F,

Color.red, 0.0F, 0.0F, new Color(64, 0, 0))

//为渲染器设置倾斜度

localBarRenderer.setSeriesPaint(0, localGradientPaint1)

localBarRenderer.setSeriesPaint(1, localGradientPaint2)

localBarRenderer.setSeriesPaint(2, localGradientPaint3)

//旋转坐标轴

CategoryAxis localCategoryAxis = localCategoryPlot.getDomainAxis()

localCategoryAxis.setCategoryLabelPositions(CategoryLabelPositions

.createUpRotationLabelPositions(0.5235987755982988D))

return localJFreeChart

}

/**

* 创建3D柱状图

*

* @return

*/

public JFreeChart createBarChart3D() {

// 设置坐标点

double[][] arrayOfDouble = { { 10.0D, 4.0D, 15.0D, 14.0D },

{ -5.0D, -7.0D, 14.0D, -3.0D }, { 6.0D, 17.0D, -12.0D, 7.0D },

{ 7.0D, 15.0D, 11.0D, 0.0D }, { -8.0D, -6.0D, 10.0D, -9.0D },

{ 9.0D, 8.0D, 0.0D, 6.0D }, { -10.0D, 9.0D, 7.0D, 7.0D },

{ 11.0D, 13.0D, 9.0D, 9.0D }, { -3.0D, 7.0D, 11.0D, -10.0D } }

// 创建图表的数据集合，第一个参数：横坐标的文字说明；第二个参数：纵坐标的文字说明；第三个参数：坐标数组

CategoryDataset paramCategoryDataset = DatasetUtilities

.createCategoryDataset("Series ", "Category ", arrayOfDouble)

// 创建3D图表

JFreeChart localJFreeChart = ChartFactory.createBarChart3D(

"3D Bar Chart Demo", "Category", "Value", paramCategoryDataset,

PlotOrientation.VERTICAL, true, true, false)

// 得到横坐标点集合对象

CategoryPlot localCategoryPlot = localJFreeChart.getCategoryPlot()

// 设置方格可见

localCategoryPlot.setDomainGridlinesVisible(true)

// 得到坐标轴

CategoryAxis localCategoryAxis = localCategoryPlot.getDomainAxis()

// 设置标注点位置

localCategoryAxis.setCategoryLabelPositions(CategoryLabelPositions

.createUpRotationLabelPositions(0.3926990816987241D))

// 创建3D柱状图渲染对象

BarRenderer3D localBarRenderer3D = (BarRenderer3D) localCategoryPlot

.getRenderer()

// 设置超出边界不可见

localBarRenderer3D.setDrawBarOutline(false)

// 返回图表对象

return localJFreeChart

}

}

是要生成excel还是柱状图，如果是单纯的生成柱状图，建议使用插件，推荐highcharts，类似这种的。

如果要生成柱状图并且还要导出到excel，用POI或者利用Jacob技术。POI里边应该有相关的类，参考这篇http://blog.csdn.net/siyemuzi/article/details/23839547

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