<!-- from JSP1.jsp to JSP2.jsp -->
<!-- JSP1.jsp中的form -->
<form action="File/JSP2.jsp">

<!-- from JSP2.jsp to JSP1.jsp -->
<!-- JSP2.jsp中的form -->
<form action="../JSP1.jsp">

//Servlet1.java 的映射地址
@WebServlet(name = "Servlet1", urlPatterns = { "/Servlet1" })

<!-- from JSP2.jsp to Servlet1 -->
<!-- JSP2.jsp中的form -->
<form action="../Servlet1">

//修改servlet1的映射地址后
@WebServlet(name = "Servlet1", urlPatterns = { "/File/Servlet1" })

<!-- from JSP2.jsp to Servlet1 -->
<!-- JSP2.jsp中的form -->
<form action="Servlet1">

//再次修改servlet1的映射地址后，映射到virtualFile虚拟目录
@WebServlet(name = "Servlet1", urlPatterns = { "/virtualFile/Servlet1" })

<!-- from JSP2.jsp to Servlet1 -->
<!-- JSP2.jsp中的form -->
<form action="../virtualFile/Servlet1">

//相对于当前jsp的相对路径跳转到servlet，同时传递参数id = 111，111为String类//在servlet页面可以通过 request.getPatameter("id")获取111
<a href="servlet1?id=111">点击跳转到servlet1</a>

//Servlet1.java 的映射地址
@WebServlet(name = "Servlet1", urlPatterns = { "/Servlet1" }) 

//利用getServletContext().getRealPath()获取web工程的绝对路径
String filePath = this.getServletContext().getRealPath("/sourceFile/1.txt");
//filePath=// D:\tomcat\apache-tomcat-8.0.50-windows-x64\apache-tomcat-8.0.50\webapps\test3\sourceFile\1.txt
BufferedReader br = new BufferedReader(new FileReader(filePath));

//Servlet1.java 的映射地址
@WebServlet(name = "Servlet1", urlPatterns = { "/Servlet1" }) 

//访问src中的文件，要按照tomcat中的工程目录获取绝对路径
//servlet不要映射到虚拟目录
String filePath = this.getServletContext().getRealPath("/WEB-INF/classes/2.txt");
BufferedWriter br = new BufferedWriter(new FileWriter(filePath));

//重定向使用相对路径，url发生改变
response.sendRedirect("File/JSP2.jsp");

//相对路径
RequestDispatcher rd = request.getRequestDispatcher("Servlet2");
rd.forward(request,response);
//绝对路径
RequestDispatcher rd = request.getRequestDispatcher("/Servlet2");
rd.forward(request,response);              

//利用class获取本类所在的目录（不含pacakage，只到classes），
//利用getResource()获取资源文件绝对路径
//在webContent中则要两次返回上级目录（WEB-INF，工程名URLTest）
File filePath = new File(NormalClass.class.getClassLoader().getResource("../../sourceFile/1.txt").getPath());
FileInputStream fn = new FileInputStream(filePath);

//利用class获取本类所在的目录（不含pacakage，只到classes），
//利用getResource()获取资源文件绝对路径
File filePath = new File(NormalClass.class.getClassLoader().getResource("2.txt").getPath());
FileInputStream fn = new FileInputStream(filePath);

<!-- from JSP2.jsp to Servlet1 -->
<!-- JSP2.jsp中的form -->
<form action="../Servlet1">

<!-- from JSP2.jsp to Servlet1 -->
<!-- JSP2.jsp中的form -->
<form action="${pageContext.request.contextPath}/Servlet1">