jsp+mysql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:<%@page contentType="text/html;charset=GB2312"%>*注:GB2312为GBK之子集。二.记录显示乱码: 1.MySQL默人语言为latin1_swedish_ci,即拉丁语,所以取出的中文全是乱码。*解决方案: 1.将charset设为8859_1即:<%@page contentType="text/html;charset=8859_1"%> 这个方法只能暂时缓解字符显示问题,并权益之计。因为8859_1为字节型字库,并非字型字库,故在非全角状态下,将出现半字乱码,表现为“?”。 2.在数据库连接语句中加上?useUnicode=true;characterEncoding=GBK,如: jdbc:mysql://localhost/dbname?useUnicode=true;characterEncoding=GBK*注:一般教科书上都会加上localhost:3306,因为默认端口为3306,故可舍去!同时,请使用连接池的朋友注意,在注册xml文件时,是不可以单独出现“;”的,所以必须使用“&”,即:jdbc:mysql://localhost/dbname?useUnicode=true&characterEncoding=GBK。 否则提示出错:Parse Fatal Error at line 213 column 91: The reference to entity "characterEncoding" must end with the ';' delimiter. org.xml.sax.SAXParseException: The reference to entity "characterEncoding" must end with the ';' delimiter. at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Un known Source) 也曾有人提意:在MySQL的my.ini文件中加入default-character-set=gbk,本人不赞同此法,因为这样破坏了原有的环境,除非这是MySQL的第一个站点。三.request传递乱码: 1.也许,此时你已经可以正常使用系统了,那么恭喜~乱码问题已经离开你了!但是,大伙通常都没那么走运,乱码问题依旧存在。也许,这时你向数据库添加了一条记录以测试系统,可是此时显示出的还是乱码。那么可以肯定是Request参数传递出错!那么先写个测试语句:<%= request.getParameter(“Para”) %>,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:package org.leo.filter; 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 { /** * The default character encoding to set for requests that pass through * this filter. */ protected String encoding = null; /** * The filter configuration object we are associated with. If this value * is null, this filter instance is not currently configured. */ protected FilterConfig filterConfig = null; /** * Should a character encoding specified by the client be ignored? */ protected boolean ignore = true; /** * Take this filter out of service. */ public void destroy() { this.encoding = null; this.filterConfig = null; } /** * Select and set (if specified) the character encoding to be used to * interpret request parameters for this request. * * @param request The servlet request we are processing * @param result The servlet response we are creating * @param chain The filter chain we are processing * * @exception IOException if an input/output error occurs * @exception ServletException if a servlet error occurs */ 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); } /** * Place this filter into service. * * @param filterConfig The filter configuration object * *encoding * UTF-8 * */ 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; } /** * Select an appropriate character encoding to be used, based on the * characteristics of the current request and/or filter initialization * parameters. If no character encoding should be set, return * null. * * The default implementation unconditionally returns the value configured * by the encoding initialization parameter for this * filter. * * @param request The servlet request we are processing */ protected String selectEncoding(ServletRequest request) { return (this.encoding); } } * The default implementation unconditionally returns the value configured * by the encoding initialization parameter for this * filter. * * @param request The servlet request we are processing */ protected String selectEncoding(ServletRequest request) { return (this.encoding); } } web.xml 加入如下内容: <filter> <filter-name>SetCharacterEncoding</filter-name> <filter-class>org.leo.filter.SetCharacterEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>SetCharacterEncoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
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:<%@page contentType="text/html;charset=GB2312"%>*注:GB2312为GBK之子集。二.记录显示乱码: 1.MySQL默人语言为latin1_swedish_ci,即拉丁语,所以取出的中文全是乱码。*解决方案: 1.将charset设为8859_1即:<%@page contentType="text/html;charset=8859_1"%> 这个方法只能暂时缓解字符显示问题,并权益之计。因为8859_1为字节型字库,并非字型字库,故在非全角状态下,将出现半字乱码,表现为“?”。 2.在数据库连接语句中加上?useUnicode=true;characterEncoding=GBK,如:
jdbc:mysql://localhost/dbname?useUnicode=true;characterEncoding=GBK*注:一般教科书上都会加上localhost:3306,因为默认端口为3306,故可舍去!同时,请使用连接池的朋友注意,在注册xml文件时,是不可以单独出现“;”的,所以必须使用“&”,即:jdbc:mysql://localhost/dbname?useUnicode=true&characterEncoding=GBK。 否则提示出错:Parse Fatal Error at line 213 column 91: The reference to entity "characterEncoding" must end with the ';' delimiter.
org.xml.sax.SAXParseException: The reference to entity "characterEncoding" must
end with the ';' delimiter.
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Un
known Source) 也曾有人提意:在MySQL的my.ini文件中加入default-character-set=gbk,本人不赞同此法,因为这样破坏了原有的环境,除非这是MySQL的第一个站点。三.request传递乱码: 1.也许,此时你已经可以正常使用系统了,那么恭喜~乱码问题已经离开你了!但是,大伙通常都没那么走运,乱码问题依旧存在。也许,这时你向数据库添加了一条记录以测试系统,可是此时显示出的还是乱码。那么可以肯定是Request参数传递出错!那么先写个测试语句:<%= request.getParameter(“Para”) %>,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:package org.leo.filter;
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
{
/**
* The default character encoding to set for requests that pass through
* this filter.
*/
protected String encoding = null;
/**
* The filter configuration object we are associated with. If this value
* is null, this filter instance is not currently configured.
*/
protected FilterConfig filterConfig = null;
/**
* Should a character encoding specified by the client be ignored?
*/
protected boolean ignore = true; /**
* Take this filter out of service.
*/
public void destroy()
{
this.encoding = null;
this.filterConfig = null;
} /**
* Select and set (if specified) the character encoding to be used to
* interpret request parameters for this request.
*
* @param request The servlet request we are processing
* @param result The servlet response we are creating
* @param chain The filter chain we are processing
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet error occurs
*/
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);
}
/**
* Place this filter into service.
*
* @param filterConfig The filter configuration object
*
*encoding
* UTF-8
*
*/
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;
} /**
* Select an appropriate character encoding to be used, based on the
* characteristics of the current request and/or filter initialization
* parameters. If no character encoding should be set, return
* null.
*
* The default implementation unconditionally returns the value configured
* by the encoding initialization parameter for this
* filter.
*
* @param request The servlet request we are processing
*/
protected String selectEncoding(ServletRequest request)
{
return (this.encoding);
}
}
* The default implementation unconditionally returns the value configured
* by the encoding initialization parameter for this
* filter.
*
* @param request The servlet request we are processing
*/
protected String selectEncoding(ServletRequest request)
{
return (this.encoding);
}
}
web.xml
加入如下内容:
<filter>
<filter-name>SetCharacterEncoding</filter-name>
<filter-class>org.leo.filter.SetCharacterEncodingFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SetCharacterEncoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>