如何将公钥交换到客户端.我使用私钥使用RSA算法加密文档(文本文件),然后使用序列化将公钥存储为文件中的java.security.Key对象.我想了解序列化公钥对象的完整性这是安全的选择或任何其他选择.
如何在jpanel中动态添加组件?当我点击按钮时,我有添加按钮,组件应该添加到JPanel.
我的问题是当我点击添加按钮时,向jpanel添加一个文本字段和按钮,用户可以根据我必须将它们添加到jpanel的任意次数点击添加按钮.我已将scrollerpane添加到我的jpanel,并且jpanel布局管理器设置为null.
我必须根据某些条件将日志信息放在两个单独的日志文件中.如何做到这一点.这是我的logging.properties文件
log4j.rootLogger=debug, stdout, R
log4j.appender.stdout=org.apache.log4j.RollingFileAppender
log4j.appender.stdout.File=${catalina.home}/logs/std.log
log4j.appender.stdout.MaxFileSize=200KB
log4j.appender.stdout.MaxBackupIndex=2
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d [%c] %p - %m%n
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=${catalina.home}/logs/demo.log
log4j.appender.R.MaxFileSize=200KB
log4j.appender.R.MaxBackupIndex=2
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%d [%c] %p - %m%n
Run Code Online (Sandbox Code Playgroud) 我的要求是在长度为10 ^ 15的整数数组中找到一个重复的数字.我需要在一次传递中找到一个副本.我知道从数组中找到重复数字的方法(逻辑),但是如何处理如此大的数字.
如何使用Java Swing库绘制水平线?我知道我需要覆盖,paint(Graphics g)
但我不确定该方法应该放什么.
@Override
public void paint(Graphics g)
{
// What goes here?
}
Run Code Online (Sandbox Code Playgroud) 如何在java swing中为JButton创建Enter键焦点?
我这样做了
btn_Login.registerKeyboardAction(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("enter key pressed");
}
}, KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0,false), txt_Username.WHEN_FOCUSED);
Run Code Online (Sandbox Code Playgroud)
但没有工作
我编写了一个java代码,用于使用以下字符串更新元素值
<![CDATA[test]]>
Run Code Online (Sandbox Code Playgroud)
但它以下列方式保存在xml文件中
<value><![CDATA[test]]></value>
Run Code Online (Sandbox Code Playgroud)
如何避免这些建议.
我试图序列化HttpSession对象并得到以下例外
java.io.NotSerializableException: org.apache.catalina.session.StandardSessionFacade
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302)
at com.tps.Session.saveSession(Session.java:16)
at org.apache.jsp.setSession_jsp._jspService(setSession_jsp.java:56)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)
Run Code Online (Sandbox Code Playgroud)