有時需要對請求或返回的資料進行加密，那麼SpringBoot就提供了支援，可對請求體進行處理，也可對響應體進行處理。

1.對請求體處理

對響應體進行處理，需要實現RequestBodyAdvice介面，重寫方法。

package com.zys.example.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.core.MethodParameter;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;

@Component
@ControllerAdvice
@Slf4j
 
public class DecodeRequestBodyAdvice implements RequestBodyAdvice {


    @Override
    public boolean supports(MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return true;
    }

    @Override
    public HttpInputMessage beforeBodyRead(HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        
 
//獲取請求頭資訊
        String header = httpInputMessage.getHeaders().getFirst("header");
        log.info("獲取的請求頭header:{}", header);
        String body = null;
        try {
            // 從流中提取資料
            InputStream is = httpInputMessage.getBody();
            byte[] data = new byte[is.available()];
            
 
is.read(data);
            body = new String(data, StandardCharsets.UTF_8);
            log.info("請求的資料，{}", body);
            //對資料進行處理 
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new DecodedHttpInputMessage(httpInputMessage.getHeaders(), new ByteArrayInputStream(body.getBytes(StandardCharsets.UTF_8)));
    }

    @Override
    public Object afterBodyRead(Object body, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return body;
    }

    @Override
    public Object handleEmptyBody(Object body, HttpInputMessage httpInputMessage, MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return body;
    }

    static class DecodedHttpInputMessage implements HttpInputMessage {
        HttpHeaders headers;
        InputStream body;

        public DecodedHttpInputMessage(HttpHeaders headers, InputStream body) {
            this.headers = headers;
            this.body = body;
        }

        @Override
        public InputStream getBody() {
            return body;
        }

        @Override
        public HttpHeaders getHeaders() {
            return headers;
        }
    }
}

需要注意是，其僅針對@RequestBody註解生效，也就是說要必須是POST請求，使用@RequestBody註解接收，才能執行上述的操作。否則不生效，如下：

@RestController
public class TestController {

    @PostMapping("/test")
    public JSONObject get(@RequestBody JSONObject json) {
        return json;
    }
}

2.對響應體處理

對響應體進行處理，需要新建類，實現ResponseBodyAdvice介面，重寫方法。

package com.zys.example.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

@Component
@ControllerAdvice
@Slf4j
public class EncodeResponseBodyAdvice implements ResponseBodyAdvice<Object> {

    @Override
    public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) {
        //若返回false則下面的配置不生效
        return true;
    }

    @Override
    public Object beforeBodyWrite(Object body, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        //獲取請求頭資訊,需要時獲取
        String header = serverHttpRequest.getHeaders().getFirst("header");
        log.info("獲取的請求頭header:{}",header);
        //body即是返回的資料，可對其進行處理後返回，如加密
        return body;
    }
}