JSP声明的基本语法是：<%! 变量定义/方法定义/类%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page language="java" import="java.util.*"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP声明例子</title> <%!int x, y = 60, z; String name = "John"; Date date = new Date();%> <%!int add(int m, int n) { int result = 0; result = m + n; return result; }%> <%!int chengji(int m, int n) { int result = 0; result = m + n; return result; }%> <%!class Circle { double r; Circle(double r) { super(); this.r = r; } double area() { return Math.floor(Math.PI * r * r); } }%> </head> <body> <% out.print("我的名字：" + name); out.print("<br/><br/>"); out.print("x的值为：" + x); out.print("<br/><br/>"); out.print("y的值为：" + y); out.print("<br/><br/>"); out.print("z的值为：" + z); out.print("<br/><br/>"); out.print("现在的时间为：" + date); out.print("<br/><br/>"); out.print("10与20的和为：" + add(10, 20)); out.print("<br/><br/>"); out.print("10与20的积为：" + chengji(10, 20)); %> <br /> <br /> <% Circle c = new Circle(6); out.print("半径为6的圆面积为：" + c.area()); %> </body> </html>
JSP表达式的作用是将动态信息显示在页面中，语法：<%=变量或者表达式%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page language="java" import="java.util.*"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>JSP声明例子</title> <%!int x, y = 60, z; String name = "John"; Date date = new Date();%> <%!int add(int m, int n) { int result = 0; result = m + n; return result; }%> <%!int chengji(int m, int n) { int result = 0; result = m + n; return result; }%> <%!class Circle { double r; Circle(double r) { super(); this.r = r; } double area() { return Math.floor(Math.PI * r * r); } }%> </head> <body> <% out.print("我的名字：" + name); out.print("<br/><br/>"); out.print("x的值为：" + x); out.print("<br/><br/>"); out.print("y的值为：" + y); out.print("<br/><br/>"); out.print("z的值为：" + z); out.print("<br/><br/>"); out.print("10与20的和为：" + add(10, 20)); out.print("<br/><br/>"); out.print("10与20的积为：" + chengji(10, 20)); %> <br /><br /> 当前的时间为：<%= date%> <br /><br /> <% Circle c = new Circle(6); out.print("半径为6的圆面积为：" + c.area()); %> </body> </html>