JSP的开发学

网站开发中JSP应用大量存在，对JSP进行一些配置和优化对有益于高效开发。下面是我开发过程中对jsp优化方法和异常解决的一些总结。

1、jsp页面配置
（1）页头设置

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>

2、异常处理
（1）contentType 错误

org.apache.jasper.JasperException: /WEB-INF/views/forum/post/asdas.jsp (line: 7, column: 1) Page directive: illegal to have multiple occurrences of contentType with different values (old: text/html; charset=UTF-8, new: text/html;charset=UTF-8)
    org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:42)
    org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:443)
    org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:237)
    org.apache.jasper.compiler.Validator$DirectiveVisitor.visit(Validator.java:135)
    org.apache.jasper.compiler.Node$PageDirective.accept(Node.java:589)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2392)
    org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2444)
    org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2450)
    org.apache.jasper.compiler.Node$Root.accept(Node.java:474)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2392)
    org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2444)
    org.apache.jasper.compiler.Validator$DirectiveVisitor.visit(Validator.java:101)
    org.apache.jasper.compiler.Node$IncludeDirective.accept(Node.java:653)
    org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2392)

错误原因： contentType=”text/html; charset=UTF-8”中，”text/html;”与”charset=UTF-8”之间缺少空格。
（2）EL表达式异常