今天学习了jsp的控制流语句。
判断语句:
If…else块,请看下面这个例子:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%! int day = 3; %> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>菜鸟教程(runoob.com)</title> </head> <body> <h3>IF...ELSE 实例</h3> <% if (day == 1 | day == 7) { %> <p>今天是周末</p> <% } else { %> <p>今天不是周末</p> <% } %> </body> </html>
现在来看看switch…case块,与if…else块有很大的不同,它使用out.println(),并且整个都装在脚本程序的标签中,就像下面这样:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%! int day = 3; %> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>菜鸟教程(runoob.com)</title> </head> <body> <h3>SWITCH...CASE 实例</h3> <% switch(day) { case 0: out.println("星期天"); break; case 1: out.println("星期一"); break; case 2: out.println("星期二"); break; case 3: out.println("星期三"); break; case 4: out.println("星期四"); break; case 5: out.println("星期五"); break; default: out.println("星期六"); } %> </body> </html>
在JSP程序中可以使用Java的三个基本循环类型:for,while,和 do…while。
让我们来看看for循环的例子,以下输出的不同字体大小的"菜鸟教程":
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%! int fontSize; %> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>菜鸟教程(runoob.com)</title> </head> <body> <h3>For 循环实例</h3> <%for ( fontSize = 1; fontSize <= 3; fontSize++){ %> <font color="green" size="<%= fontSize %>"> 菜鸟教程 </font><br /> <%}%> </body> </html>
将上例改用 while 循环来写:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%! int fontSize=0; %> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>菜鸟教程(runoob.com)</title> </head> <body> <h3>While 循环实例</h3> <%while ( fontSize <= 3){ %> <font color="green" size="<%= fontSize %>"> 菜鸟教程 </font><br /> <%fontSize++;%> <%}%> </body> </html>