About servlet inside path problem when using OutputStream , thank

 This post last edited by the raylee2007 on 2013-03-15 10:44:39

questions: general program , implemented in java application and implemented in the servlet path settings OutputStream what ? Why the former can use relative paths , the latter can only use absolute path ?


The first is the use of java program to achieve the production of a JFreeChart, middle OutputStream that can be used normally .

  import java.awt.Font;
  import java.io.FileOutputStream;
  import java.io.OutputStream;
  
  import org.jfree.chart.ChartFactory;
  import org.jfree.chart.ChartUtilities;
  import org.jfree.chart.JFreeChart;
  import org.jfree.chart.plot.PiePlot;
  import org.jfree.chart.title.LegendTitle;
  import org.jfree.chart.title.TextTitle;
  import org.jfree.data.general.DefaultPieDataset;
  
  public class JFreeChartTest3 {
  	public static void main(String[] args) throws Exception {
  		JFreeChart chart = ChartFactory.createPieChart("某公司人员组织数据图",
  				getDataset(), true, true, false);
  		chart.setTitle(new TextTitle("某公司组织结构图", new Font("宋体", Font.BOLD
  				+ Font.ITALIC, 20)));
  
  		LegendTitle legend = chart.getLegend(0);// 设置Legend
  		legend.setItemFont(new Font("宋体", Font.BOLD, 14));
  		PiePlot plot = (PiePlot) chart.getPlot();// 设置Plot
  		plot.setLabelFont(new Font("隶书", Font.BOLD, 16));
  
  
  
  
          //------------------------------------------------------
  		OutputStream os = new FileOutputStream(
  				"WebContent/admin/images/reports/company.jpeg");
                  // 图片是文件格式的，故要用到FileOutputStream用来输出。
          //------------------------------------------------------
  
  
  
  
  
  
  		ChartUtilities.writeChartAsJPEG(os, chart, 1000, 800);
  		// 使用一个面向application的工具类，将chart转换成JPEG格式的图片。第3个参数是宽度，第4个参数是高度。
  
  		os.close();// 关闭输出流
  	}
  
  	private static DefaultPieDataset getDataset() {
  		DefaultPieDataset dpd = new DefaultPieDataset(); // 建立一个默认的饼图
  		dpd.setValue("管理人员", 25); // 输入数据
  		dpd.setValue("市场人员", 25);
  		dpd.setValue("开发人员", 45);
  		dpd.setValue("其他人员", 10);
  		return dpd;
  	}
  }
  

The second program is implemented through a servlet , but the same that path is wrong

  
  import java.awt.Font;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.jfree.chart.ChartFactory;
  import org.jfree.chart.ChartUtilities;
  import org.jfree.chart.JFreeChart;
  import org.jfree.chart.plot.PiePlot;
  import org.jfree.chart.title.LegendTitle;
  import org.jfree.chart.title.TextTitle;
  import org.jfree.data.general.DefaultPieDataset;
  
  
  public class SalesProductChartServlet extends HttpServlet {
  	private static final long serialVersionUID = 1L;
  
  	
  	public SalesProductChartServlet() {
  		super();
  		// TODO Auto-generated constructor stub
  	}
  
  	
  	protected void doGet(HttpServletRequest request,
  			HttpServletResponse response) throws ServletException, IOException {
  		JFreeChart chart = ChartFactory.createPieChart("某公司人员组织数据图",
  				getDataset(), true, true, false);
  		chart.setTitle(new TextTitle("某公司组织结构图", new Font("宋体", Font.BOLD
  				+ Font.ITALIC, 20)));
  
  		LegendTitle legend = chart.getLegend(0);// 设置Legend
  		legend.setItemFont(new Font("宋体", Font.BOLD, 14));
  		PiePlot plot = (PiePlot) chart.getPlot();// 设置Plot
  		plot.setLabelFont(new Font("隶书", Font.BOLD, 16));
  
  
  
  
  
  //-------------------------------------------------------
  		OutputStream os = new FileOutputStream(
  				"WebContent/admin/images/reports/company.jpeg");
                  // 图片是文件格式的，故要用到FileOutputStream用来输出。
                  //这里的路径如果换成绝对路径就可以正常实现
                  //报错：java.io.FileNotFoundException: WebContent\admin\images\reports\company.jpeg (系统找不到指定的路径。)
  
  //-------------------------------------------------------
  
  
  
  
  
  		ChartUtilities.writeChartAsJPEG(os, chart, 1000, 800);
  		// 使用一个面向application的工具类，将chart转换成JPEG格式的图片。第3个参数是宽度，第4个参数是高度。
  
  		os.close();// 关闭输出流
  	}
  	
  	private static DefaultPieDataset getDataset() {
  		DefaultPieDataset dpd = new DefaultPieDataset(); // 建立一个默认的饼图
  		dpd.setValue("管理人员", 25); // 输入数据
  		dpd.setValue("市场人员", 25);
  		dpd.setValue("开发人员", 45);
  		dpd.setValue("其他人员", 10);
  		return dpd;
  	}
  }
  
  

------ Solution ------------------------------------- -------
one for browser with , one is for server .
------ Solution ---------------------------------------- ----
servlet in the root directory is the WebContent
Try / admin / images / reports / company.jpeg
------ For reference only -------------------- -------------------
Why use relative paths will complain it ?
------ For reference only -------------------------------------- -
it seems to be the default path under tomcat bin folder !