后端获取请求体Body，将请求体进行解密放回Request请求,并能通过@RequestBody获取

目前系统发送的post和put请求都是没有加密数据。客户需要将请求体加密。而系统已经基本开发完成，不可能一个一个去修改发送的请求。就需要在发送请求时候在拦截器中将body进行加密。并且在后端进行请求过滤解密，并且能通过@RequestBody继续获取对象。

1.先将前端代码进行处理。在发送请求时候判断是是否是post或者是put请求，如果是就将body进行加密(本人测试用的是base64)。然后转成json格式传递（如果不转成json，而是直接用base64，就需要修改请求headers，改成"Content-Type"："application/base64"的这种格式，不然后端获取不到body。如果是用application/base64，后端在解密后还需要将请求头改成"Content-Type", "application/json"）。

2.后端创建一个过滤器并注册过滤器。这里需要注意一下，当我们获取到加密请求体后，实际的body已经被消费掉了。需要通过filterChain.doFilter(new DecryptingHttpServletRequestWrapper(request, decryptedData), response);这行代码将我们解密后的数据放回请求体

package cn.com.oceansoft.osc.ms.config;

import cn.com.oceansoft.osc.ms.common.utils.StringUtils;
import com.alibaba.fastjson.JSON;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.Base64;

/**
 * @author 
 */
public class DecryptingOncePerRequestFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {
        if ("POST".equalsIgnoreCase(request.getMethod()) || "PUT".equalsIgnoreCase(request.getMethod())) {
            // 读取加密的请求体数据
            String encryptedData = readRequestBody(request);
            if (StringUtils.isNotBlank(encryptedData)) {
                //获取到加密的数据
                String val=(String) JSON.parseObject(encryptedData).get("encryptedData");
                // Base64解码
                String decryptedData =decrypt(val);

                // 使用自定义的请求包装器替换原始请求
                filterChain.doFilter(new DecryptingHttpServletRequestWrapper(request, decryptedData), response);

            }

        } else {
            // 对于非POST请求，继续过滤器链
            filterChain.doFilter(request, response);
        }
    }

    private String readRequestBody(HttpServletRequest request) throws IOException {
        StringBuilder stringBuilder = new StringBuilder();
        try (BufferedReader reader = request.getReader()) {
            String line;
            while ((line = reader.readLine()) != null) {
                stringBuilder.append(line);
            }
        }
        return stringBuilder.toString();
    }

    private String decrypt(String encryptedData) throws UnsupportedEncodingException {
        // 实现你的解密逻辑
        // 这里只是一个示例，需要替换为实际的解密方法
        return new String(Base64.getDecoder().decode(encryptedData), "UTF-8");
    }

    // 自定义的请求包装器
    static class DecryptingHttpServletRequestWrapper extends HttpServletRequestWrapper {
        private final String decryptedData;

        public DecryptingHttpServletRequestWrapper(HttpServletRequest request, String decryptedData) {
            super(request);
            this.decryptedData = decryptedData;
        }

        @Override
        public ServletInputStream getInputStream() throws IOException {
            final ByteArrayInputStream bais = new ByteArrayInputStream(decryptedData.getBytes("UTF-8"));
            return new ServletInputStream() {
                @Override
                public boolean isFinished() {
                    return false;
                }

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

                @Override
                public void setReadListener(ReadListener listener) {

                }

                @Override
                public int read() throws IOException {
                    return bais.read();
                }
            };
        }

        @Override
        public BufferedReader getReader() throws IOException {
            return new BufferedReader(new InputStreamReader(getInputStream()));
        }
    }
}

package cn.com.oceansoft.osc.ms.config;

import cn.com.oceansoft.osc.ms.config.DecryptingOncePerRequestFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.servlet.Filter;

/**
 * @author 
 */
@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean decryptingFilterRegistration() {
        FilterRegistrationBean registrationBean =
                new FilterRegistrationBean();
        //注册过滤器
        registrationBean.setFilter(new DecryptingOncePerRequestFilter());
        registrationBean.addUrlPatterns("/*"); // 设置过滤器应用的URL模式
        registrationBean.setOrder(1); // 设置过滤器的顺序
        return registrationBean;
    }
}