1 1.网页访问量计数 2 <%@page import="java.math.BigInteger"%> 3 <%@page import="java.io.*"%> 4 <%@page import="java.util.*"%> 5 <%@ page language="java" contentType="text/html" 6 pageEncoding="utf-8"%> 7 <!DOCTYPE html> 8 <html> 9 <head> 10 <title>网页访问量计数</title> 11 </head> 12 <body> 13 <%! 14 //定义全局变量 15 BigInteger count = null; 16 %> 17 <%! //读入文件读取方法 18 public BigInteger load(File f){ 19 BigInteger count = null; 20 try{ 21 if(f.exists()){//判断文件存不存在 22 Scanner sc = new Scanner(new FileInputStream(f)); 23 if(sc.hasNext()){ 24 count = new BigInteger(sc.next()); 25 } 26 sc.close(); 27 }else{ 28 //文件不存在,即还没有访客进行访问 29 count = new BigInteger("0"); 30 //保存到文件中 31 save(f,count); 32 } 33 }catch(Exception e){ 34 System.out.println(e); 35 } 36 return count; 37 } 38 //写出文件保存方法 39 public void save(File f,BigInteger count){ 40 try{ 41 PrintStream ps= null; 42 ps = new PrintStream(new FileOutputStream(f)); 43 ps.println(count); 44 ps.close(); 45 }catch(Exception e){ 46 System.out.println(e); 47 } 48 } 49 %> 50 <% 51 String name = this.getServletContext().getRealPath("/")+"count.txt"; 52 System.out.print(name); 53 File f = new File(name); 54 if(session.isNew()){ 55 synchronized(this){ 56 //读取数据以及保存 57 count = load(f); 58 //做自增操作 59 count = count.add(new BigInteger("1")); 60 //保存数据 61 save(f,count); 62 } 63 } 64 %> 65 <h2>您是第<%=count==null?0:count %>位访客</h2> 66 </body> 67 </html> 68 2.获取真实路径 69 <%@ page language="java" contentType="text/html" 70 pageEncoding="GBK"%> 71 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 72 <html> 73 <head> 74 <title>Insert title here</title> 75 </head> 76 <body> 77 <% 78 String path = this.getServletContext().getRealPath("/"); 79 %> 80 真实路径：<%=path%> 81 </body> 82 </html> 83 3.获取属性名称及属性 84 <%@page import="java.util.Enumeration"%> 85 <%@ page language="java" contentType="text/html" 86 pageEncoding="GBK"%> 87 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 88 <html> 89 <head> 90 <title>Insert title here</title> 91 </head> 92 <body> 93 <% 94 Enumeration en = this.getServletContext().getAttributeNames(); 95 while(en.hasMoreElements()){ 96 String name = (String)en.nextElement(); 97 %> 98 <h1><%=name %>----<%=this.getServletContext().getAttribute(name) %></h1> 99 <% 100 } 101 %> 102 </body> 103 </html> 104 4.缓冲区大小 105 <%@page import="java.util.Enumeration"%> 106 <%@ page language="java" contentType="text/html" 107 pageEncoding="GBK"%> 108 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 109 <html> 110 <head> 111 <title>Insert title here</title> 112 </head> 113 <body> 114 <% 115 int buffer = out.getBufferSize();//全部缓冲区大小 116 int unuse = out.getRemaining();//未使用缓冲区大小 117 int use = buffer-unuse; 118 %> 119 <h3>缓冲区大小<%=buffer %></h3> 120 <h3>未使用缓冲区大小<%=unuse %></h3> 121 <h3>已使用缓冲区大小<%=use %></h3> 122 </body> 123 </html> 124 5.表单内容写入、写出文件 125 <!DOCTYPE html> 126 <html> 127 <head> 128 <meta charset="GBK"> 129 <title>Insert title here</title> 130 </head> 131 <body> 132 <form action="input_context.jsp" method="post"> 133 文件名：<input type="text" name="filename"><br> 134 文件内容<textarea rows="10" cols="30" name="context"></textarea><br> 135 <input type="submit" value="保存"> 136 </form> 137 </body> 138 </html> 139 140 <%@ page language="java" contentType="text/html" 141 pageEncoding="GBK"%> 142 <%@ page import="java.io.*" %> 143 <%@ page import="java.util.*" %> 144 <%@ page import="java.lang.*" %> 145 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 146 <html> 147 <head> 148 <title>Insert title here</title> 149 </head> 150 <body> 151 <% 152 //设置统一编码 153 request.setCharacterEncoding("GBK"); 154 //获取到文件名称 文件内容 155 String filename = request.getParameter("filename"); 156 String content = request.getParameter("context"); 157 //拼凑path 内容保存于 当前路径下新建的note文件夹中， 158 String path = this.getServletContext().getRealPath("/")+"note"+File.separator+filename; 159 //判断父文件夹是否存在 160 File f = new File(path); 161 if(!f.getParentFile().exists()){ 162 f.getParentFile().mkdir();//创建文件夹 163 } 164 PrintStream ps = null; 165 ps = new PrintStream(new FileOutputStream(f)); 166 ps.println(content); 167 ps.close(); 168 System.out.println("输出成功"); 169 %> 170 <% 171 Scanner sc = new Scanner(new FileInputStream(f)); 172 sc.useDelimiter(" ");//按换行符扫描 173 StringBuffer sbu = new StringBuffer(); 174 while(sc.hasNext()){ 175 sbu.append(sc.next()).append("<br>");//显示文件内容 176 } 177 178 %> 179 <%=sbu %> 180 </body> 181 </html>