过滤器复用代码【中文乱码、HTML转义】-优快云博客

本文介绍了一个用于处理HTTP请求中的字符编码问题的过滤器，并实现了一个过滤敏感HTML标签的过滤器，确保了输入的安全性和正确解析。

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中文乱码


public class CharacterEncodingFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse resp,
            FilterChain chain) throws IOException, ServletException {


        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;

        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8");

        chain.doFilter(new MyRequest(request), response);


    }

    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub

    }

    public void destroy() {
        // TODO Auto-generated method stub

    }
}

class MyRequest extends HttpServletRequestWrapper{
    private HttpServletRequest request;
    public MyRequest(HttpServletRequest request) {
        super(request);
        this.request = request;

    }
    @Override
    public String getParameter(String name) {

        String value = this.request.getParameter(name);
        if(value==null){
            return null;
        }
        if(!this.request.getMethod().equalsIgnoreCase("get")){
            return value;
        }
        try {
            value = new String(value.getBytes("iso8859-1"),"UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
        return value;
    }
}

过滤HTML

public class HtmlFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse resp,
            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;

        chain.doFilter(new MyRequest2(request), response);

    }

    public void destroy() {
        // TODO Auto-generated method stub
    }

    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}
class MyRequest2 extends HttpServletRequestWrapper{

    private HttpServletRequest request;
    public MyRequest2(HttpServletRequest request) {
        super(request);
        this.request = request;
    }
    @Override
    public String getParameter(String name) {

        String value = this.request.getParameter(name);
        if(value==null){
            return null;
        }
        return filter(value);
    }

    public String filter(String message) {

        if (message == null)
            return (null);

        char content[] = new char[message.length()];
        message.getChars(0, message.length(), content, 0);
        StringBuffer result = new StringBuffer(content.length + 50);
        for (int i = 0; i < content.length; i++) {
            switch (content[i]) {
            case '<':
                result.append("&lt;");
                break;
            case '>':
                result.append("&gt;");
                break;
            case '&':
                result.append("&amp;");
                break;
            case '"':
                result.append("&quot;");
                break;
            default:
                result.append(content[i]);
            }
        }
        return (result.toString());

    }


}