《java遇到html--servlet篇》2015.09.16笔记

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《java遇到html--servlet篇》2015.09.16笔记
web.xml文件的配置，就是<servlet></servlet>和<servlet-mapping></servlet-mapping>标签之间添加内容。<load-on-startup></load-on-startup>就是tomcat启动时servlet的加载顺序，数字越小加载越优先；
<servlet>
<servlet-name>TestServlet1</servlet-name>
<servlet-class>servlet.TestServlet1</servlet-class>
<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>TestServlet1</servlet-name>
<url-pattern>/servlet/TestServlet1</url-pattern>

</servlet-mapping>

<servlet>
<servlet-name>TestServlet2</servlet-name>
<servlet-class>servlet.TestServlet2</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>TestServlet2</servlet-name>
<url-pattern>/servlet/TestServlet2</url-pattern>
</servlet-mapping>
2.response.setContentType("text/html;charset=utf-8");可防止中文乱码，必须写在PrintWriter out=response.getWriter();之前，不然不起作用。syso是在控制台（后台）输出，out.print()是在页面输出的；
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("TestServlet1的doGet()方法被执行...");
response.setContentType("text/html;charset=utf-8");
PrintWriter out=response.getWriter();
out.println("<html>");
out.println("<hed><title>a servlet</title></head>");
out.println("<body><h1>这是TestServlet</h1></body>");
out.println("<html>");
out.flush();
out.close();

}

3.运行时出现了一个错误，这个错误导致了其他项目也不可以运行，eclipse启动不了tomcat，但是用startup在本地是可以启动的。错误的原因是在web.xml文件的配置时粗心把类名写错了。

严重: A child container failed during startjava.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/myfirstServletDemo1]]at java.util.concurrent.FutureTask.report(FutureTask.java:122)at java.util.concurrent.FutureTask.get(FutureTask.java:188)at org

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