使用过滤器解决(Post/Get)中文乱码问题

喜欢ヅ旅行 2022-05-27 08:07 239阅读 0赞

过滤器的好处：使用了过滤器，无论是**Get/Post**方式，接收参数时，都不需要再额外的进行转码，过滤器会自动的帮我们办这件事，乱码问题很好的解决了。

**方式一：配置文件方式配置过滤器**

创建CharacterEncodingFilter类，实现Filter接口

public class CharacterEncodingFilter implements Filter { 
        private String encode = "UTF-8";
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
            String encoding = arg0.getInitParameter("encode");
            if (encoding != null) {
                encode = encoding;
            }
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) arg0;
            HttpServletResponse response = (HttpServletResponse) arg1; // post方式设置编码格式： 
            request.setCharacterEncoding(encode);
            response.setContentType("text/html;charset=" + encode);
            arg2.doFilter(new CharacterEncodingRequest(request), arg1);
        }
    
        @Override
        public void destroy() {
        }
    }
    
    /** * 对Get方式传递的请求参数进行编码 */
    class CharacterEncodingRequest extends HttpServletRequestWrapper {
        private HttpServletRequest request;
    
        public CharacterEncodingRequest(HttpServletRequest request) {
            super(request);
            this.request = request;
        }
    
        /** * 对参数重新编码 */
        @Override
        public String getParameter(String name) {
            String value = super.getParameter(name);
            if (value == null) {
                return null;
            }
            String method = request.getMethod();
            if ("Get".equalsIgnoreCase(method)) {
                try {
                    value = new String(value.getBytes("ISO8859-1"), request.getCharacterEncoding());
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
            }
            return value;
        }
    }

在web.xml中配置过滤器

<filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>com.filter.util.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encode</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping></filter-mapping>

**方式二：注解的方式配置过滤器。这种方式较为简单。对过滤器的配置，以注解的方式定义。**

@WebFilter(initParams = {
       @WebInitParam(name = "encode", value = "UTF-8")}, urlPatterns = {
       "/*"})
    public class CharacterFilter implements Filter { 
        private String encoding = "UTF-8";
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
            String encode = arg0.getInitParameter("encode");
            if (encode != null) {
                encoding = encode;
            }
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) arg0;
            HttpServletResponse response = (HttpServletResponse) arg1;
            request.setCharacterEncoding(encoding);
            response.setContentType("text/html;charset=" + encoding);
            arg2.doFilter(new CharacterEncodingRequest(request), arg1);
        }
    
        @Override
        public void destroy() {
            // TODO Auto-generated method stub
        }
    }
    
    // /** * 对Get方式传递的请求参数进行编码 */
    class CharacterEncodingRequest extends HttpServletRequestWrapper {
        private HttpServletRequest request;
    
        public CharacterEncodingRequest(HttpServletRequest request) {
            super(request);
            this.request = request;
        }
    
        /** * 对参数重新编码 */
        @Override
        public String getParameter(String name) {
            String value = super.getParameter(name);
            if (value == null) {
                return null;
            }
            String method = request.getMethod();
            if ("Get".equalsIgnoreCase(method)) {
                try {
                    value = new String(value.getBytes("ISO8859-1"), request.getCharacterEncoding());
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
            }
            return value;
        }
    }

作者： 做一个善良的人  
链接：[https://www.imooc.com/article/14356][https_www.imooc.com_article_14356]  
来源：慕课网

[https_www.imooc.com_article_14356]: https://www.imooc.com/article/14356