2. JSP script

JSP script

JSP scripts contain JSP expressions, declarative identities, and scripting programs. With these identities, you can declare variables, define methods, and perform operations on various expressions in a JSP page as if you were writing a Java program

1. Application of code snippets in JSP

　　Syntax format: <% java code or script code%>

Code snippets are more flexible to use, either as Java code or as built-in objects provided by JSPs

For example:

　　

    <%         int num=1;          for (int i=1;i<=10;i++) {            num*=i;        }        Out.println (the factorial of "10 is:" +num)     ; %>

2. Using JSP expressions

A JSP expression is used to output information in a page, which can be inserted into the text of a Web page for output text content or inserted into HTML tags to dynamically set property values

　　JSP expression Syntax format: <%= expression%>

　　

    <%         Stringname="Admin"; StringPhoto="1.jpg"; %>User name:<%=name%>Photos<imgsrc= "<%=photo%>">

Note: You cannot have spaces before% and =

3. Declaration of Identity

You can also define member variables and member methods in a JSP page as you would write a Java file, which declares the identity of the application. Defining a variable or method in a JSP page with a claim identity is global.

Syntax format: <%! Declaration order or method%>

Because the variable that declares the identity is global, there is a thread-safety problem when multiple users are concurrently accessing it, and this approach applies very little

　　

    <%!        int count=0;          Public int GetCount () {            return + +count        ;     } %>          You are <%=getcount ()%> Visitors

2. JSP script