利用filter过滤器将字符编码转变为utf-8。

过滤器位置

1.新建EncodingFilter.java文件

package encoding;

import java.io.*;
import javax.servlet.*;

public class EncodingFilter implements Filter {
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        try {
            request.setCharacterEncoding("utf-8");
            response.setCharacterEncoding("utf-8");
        } catch (Exception e) {
        }

        chain.doFilter(request, response);
    }

    public void destroy() {

    }
}

2.修改web.xml文件（如果没有就自己新建一个）

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <filter>
        <display-name>encoding</display-name>
        <filter-name>encoding</filter-name>
        <filter-class>encoding.EncodingFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>