SpringBoot过滤器参数全角转半角

最新推荐文章于 2022-01-05 10:32:05 发布

itdragons

最新推荐文章于 2022-01-05 10:32:05 发布

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分类专栏： Java 文章标签： java全角转半角

本文链接：https://blog.youkuaiyun.com/itdragons/article/details/103362086

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本文介绍了一个参数过滤器的实现，该过滤器能够将接收到的全角字符转换为半角字符，适用于处理HTTP请求参数，确保数据的一致性和正确性。

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import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * 参数过滤器,全角转半角
 * @author itdragons 2019年12月3日09:23:25
 */
@Component
@WebFilter(filterName = "ParamsFilter", urlPatterns = "/")
public class ParamsFilter implements Filter {


    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // System.out.println("----------------------->过滤器被创建");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        // System.out.println("--------------------->过滤器：请求地址" + ((HttpServletRequest) servletRequest).getRequestURI());
        ServletRequest requestWrapper = null;
        if(servletRequest instanceof HttpServletRequest) {
            requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
        }

        if(null == requestWrapper) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            filterChain.doFilter(requestWrapper, servletResponse);
        }
    }

    @Override
    public void destroy() {
        //System.out.println("----------------------->过滤器被销毁");
    }

    public class RequestWrapper extends HttpServletRequestWrapper {

        public RequestWrapper(HttpServletRequest request) {
            super(request);
        }

        @Override
        public Map<String,String[]> getParameterMap() {
            Map<String,String[]> map = new LinkedHashMap<>();
            Map<String,String[]> parameters = super.getParameterMap();
            for (String key : parameters.keySet()) {
                String[] values = parameters.get(key);
                for (int i = 0; i < values.length; i++) {
                    //全角转半角
                    values[i] = fullWidth2halfWidth(values[i]);
                }
                map.put(key, values);
            }
            return map;
        }

        @Override
        public ServletInputStream getInputStream() throws IOException {
            //为空，直接返回
            String json = IOUtils.toString(super.getInputStream(), StandardCharsets.UTF_8);
            if (StringUtils.isBlank(json)) {
                return super.getInputStream();
            }

            //全角转半角
            json = fullWidth2halfWidth(json);
            final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes(StandardCharsets.UTF_8));
            return new ServletInputStream() {
                @Override
                public boolean isFinished() {
                    return true;
                }

                @Override
                public boolean isReady() {
                    return true;
                }

                @Override
                public void setReadListener(ReadListener readListener) {

                }

                @Override
                public int read() {
                    return bis.read();
                }
            };
        }
    }

    /**
     * 全角字符串转换半角字符串
     *
     * @param fullWidthStr
     *         非空的全角字符串
     * @return 半角字符串
     */
    private static String fullWidth2halfWidth(String fullWidthStr) {
        if (null == fullWidthStr || fullWidthStr.length() <= 0) {
            return "";
        }
        char[] charArray = fullWidthStr.toCharArray();
        //对全角字符转换的char数组遍历
        for (int i = 0; i < charArray.length; ++i) {
            int charIntValue = (int) charArray[i];
            //如果符合转换关系,将对应下标之间减掉偏移量65248;如果是空格的话,直接做转换
            if (charIntValue >= 65281 && charIntValue <= 65374) {
                charArray[i] = (char) (charIntValue - 65248);
            } else if (charIntValue == 12288) {
                charArray[i] = (char) 32;
            }
        }
        return new String(charArray);
    }

}