2种解决JSP中request乱码问题

        JSP日常使用中，我们会经常遇到乱码问题，比如：用request得到的用户输入的中文怎么是乱码，把汉字写到数据库怎么是乱码，等等一些关于汉字乱码的问题。
其实这个问题很简单，管它汉字不汉字，还是日文，还是其他的什么双字节的语言，我们一律把它当作UTF-8看待。

（一）request中的双字节文字

好下面我们就来实现在整个应用程序中使用UTF-8编码工作，之所以选择UTF-8不仅仅之于上述原因，我们知道java的就是基于在UTF-8之上的，所以我们选择UTF-8应该没错，我们首先把我们的java, .jsp文件都用UTF-8编码来保存，如果以前的没有用UTF-8保存也无所谓，但是建议以后写的都用UTF-8来保存。并在.jsp里面写:<%@page contentType="text/html; charset=UTF-8"%>而不是<%@page contentType="text/html; charset=UTF-8"%>
然后在web.xml添加下面一段：
<web-app>
...
<filter>
    <filter-name>Set Character Encoding</filter-name>
    <filter-class>com.redv.projects.eduadmin.util.filters.SetCharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>Set Character Encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
...
</web-app>

其中com.redv.projects.eduadmin.util.filters.SetCharacterEncodingFilter的代码如下：

package com.redv.projects.eduadmin.util.filters;

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;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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);           //就是这句话在工作的啦，它：Overrides the name of the character encoding used in the body of this request. This method must be called prior to reading request parameters or reading input using getReader().
      }
    }

    // Pass control on to the next filter
    chain.doFilter(request, response);

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2种解决JSP中request乱码问题