JSP+MySQL开发中乱码困扰？这里有答案！

JSP+MySQL+Tomcat+Apache乱码解决

乱码问题已历来已久，在开源环境下，乱码问题更是令程序员措手不及。本人在Unix（Freebsd）下的一次乱码经历可谓经典，故撰以此文以滋效尤！

我将本次所遇乱码归为三类：

１．页面字符乱码

２．记录显示乱码

３．request传递乱码

以下将对上述三类乱码进行解析：

一．页面字符乱码：

１．大小写不一致：

org.apache.jasper.JasperException: /top.jsp(1,1) Page directive: illegal to have multiple occurrences of contentType with different values (old: text/html;charset=gb2312, new: text/html;charset=GB2312)

２．间隔不一致：

org.apache.jasper.JasperException: /top.jsp(1,1) Page directive: illegal to have multiple occurrences of contentType with different values (old: text/html; charset=GB2312, new: text/html;charset=GB2312)

＊解决方案：

首先，在Apache中增加AddDefaultCharset GB2312或AddDefaultCharset GBK

其次，统一使用页面编码定义，如：，ＯＫ，果然是乱。那么，现在有两种解决方法。

＊解决方案：

１．加上这条语句：request.setCharacterEncoding("gbk");

在一／两页上可行，但此法也非权益之计。

２．注册SetCharacterEncodingFilter类：

首先，编写SetCharacterEncodingFilter.java文件，代码如下：

package cn.com.jsp;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.UnavailableException;

public class SetCharacterEncodingFilter implements Filter {

protected String encoding = null;

protected FilterConfig filterConfig = null;

protected boolean ignore = true;

public void destroy() {

this.encoding = null;

this.filterConfig = null;

}

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException,

ServletException {

// Conditionally select and set the character encoding to be used

if (ignore || (request.getCharacterEncoding() == null)) {

String encoding = selectEncoding(request);

if (encoding != null) {

request.setCharacterEncoding(encoding);

}

}

// Pass control on to the next filter

chain.doFilter(request, response);

}

public void init(FilterConfig filterConfig) throws ServletException {

this.filterConfig = filterConfig;

this.encoding = filterConfig.getInitParameter("encoding");

String value = filterConfig.getInitParameter("ignore");

if (value == null) {

this.ignore = true;

} else if (value.equalsIgnoreCase("true")) {

this.ignore = true;

} else if (value.equalsIgnoreCase("yes")) {

this.ignore = true;

} else {

this.ignore = false;

}

}

protected String selectEncoding(ServletRequest request) {

return (this.encoding);

}

}

此文件为request过滤类，在全局编译前需进行注册。

注册文件为：<!--wroo-->/WEB-INF/web.xml。

在此文件中加入如下代码即可：

wwwroot

MySQL Test App

setCharacterEncodingFilter

setCharacterEncodingFilter

setCharacterEncodingFilter

cn.com.jsp.SetCharacterEncodingFilter

encoding

GBK

setCharacterEncodingFilter

/*

……

ＯＫ，现在可以编译你的SetCharacterEncodingFilter.java文件啦！

至此，乱码将与你格格不入！