jfreechart图片默认存放路径修正.doc

修改JFreeChart 图片的存放路径 JFreeChart会把生成的图片,默认放在应用服务器的temp目录下,有的时候我们是不能放在该目录下的,需要改变这个存放路径 发现jfreechart的ServletUtilities类里有 protected static void createTempDir() {??????? String tempDirName = System.getProperty(java.io.tmpdir);默认的临时文件 Users\ADMINI~1\AppData\Local\Temp\ ??????? if (tempDirName == null) {??????????? throw new RuntimeException(应用服务器目录下不存在temp目录或该目录无法创建);??????? } ??????? // create the temporary directory if it doesnt exist??????? File tempDir = new File(tempDirName);??????? if (!tempDir.exists()) {??????????? tempDir.mkdirs();??????? }??? } 该方法创建了默认的图片存放路径 在该类的saveChartAsPNG() 和saveChartAsJPEG () 里被调用,产生图形,因此我们的思路就是将ServletUtilities的saveChartAsPNG() 和saveChartAsJPEG () 这2个方法改造成自己定义的方法 修改前源文件如下: ??? public static String saveChartAsJPEG(JFreeChart chart, int width,???????????? int height, ChartRenderingInfo info, HttpSession session)??????????? throws IOException { ??????? if (chart == null) {??????????? throw new IllegalArgumentException(Null chart argument.);?????????? }??????? //注意,源文件使用了默认路径????????ServletUtilities.createTempDir();??????? String prefix = ServletUtilities.tempFilePrefix;??????? if (session == null) {??????????? prefix = ServletUtilities.tempOneTimeFilePrefix;?????????? }??????? File tempFile = File.createTempFile(prefix, .jpeg,???????????????? new File(System.getProperty(java.io.tmpdir)));??????? ChartUtilities.saveChartAsJPEG(tempFile, chart, width, height, info);??????? if (session != null) {??????????? ServletUtilities.registerChartForDeletion(tempFile, session);??????? }??????? return tempFile.getName(); ??? } ? 修改后如下: ??? public static String saveChartAsJPEG(JFreeChart chart, int width,???????????? int height, ChartRenderingInfo info, HttpSession session)??????????? throws IOException { //从application中读取出临时文件目录,我事先已经在系统启动时,创建了目录??????????? File tempDr=(File)session.getServletContext().getAttribute(tempDirectory);????????????????????? if (chart == null) {??????????? throw new IllegalArgumentException(c