我想知道这些servlet方法.我对这些方法有所了解
doPost对于参数数字没有限制doGet.doGet比...更快doPost.doPost是安全的doGet.我的问题是,因为这些方法采用相同的参数并完成我们实施的过程.那么major difference这些方法和之间的关系是什么At which specific situation each of this method is used to process.
I found that declaring a variable as static makes no sense在多线程中.我认为,这是因为every thread has its own stack.这是唯一的原因吗？
我知道static variables should be used within synchronized block.但为什么？
我遇到了运行时异常.我想从android设备创建一个PDF文档.为此,我使用了iText库.
这是我创建PDF的代码
Document document = new Document();
PdfWriter.getInstance(document, outStream);
document.open();
document.add(new Paragraph(data));
document.close();
代码工作正常.它正在成功创建PDF.但它让我在运行时说例外
06-14 10:09:20.491: W/dalvikvm(764): Unable to resolve superclass of Lcom/itextpdf/awt/PdfGraphics2D; (1251)
06-14 10:09:20.491: W/dalvikvm(764): Link of class 'Lcom/itextpdf/awt/PdfGraphics2D;' failed
06-14 10:09:20.491: E/dalvikvm(764): Could not find class 'com.itextpdf.awt.PdfGraphics2D', referenced from method com.itextpdf.text.pdf.PdfContentByte.createGraphics
06-14 10:09:20.491: W/dalvikvm(764): VFY: unable to resolve new-instance 480 (Lcom/itextpdf/awt/PdfGraphics2D;) in Lcom/itextpdf/text/pdf/PdfContentByte;
06-14 10:09:25.280: E/dalvikvm(764): Could not find class 'org.bouncycastle.cert.X509CertificateHolder', referenced from method com.itextpdf.text.pdf.PdfReader.readDecryptedDocObj
06-14 10:09:25.280: W/dalvikvm(764): VFY: unable to resolve new-instance 1612 (Lorg/bouncycastle/cert/X509CertificateHolder;) in Lcom/itextpdf/text/pdf/PdfReader; …