如何使用拦截器获取请求的入参并将其转化为Java对象详解

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

public class CachedBodyHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private byte[] requestBody;

    public CachedBodyHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        // 从 InputStream 读取数据，缓存请求体内容
        InputStream inputStream = request.getInputStream();
        this.requestBody = inputStream.readAllBytes();  // 将流中的数据读取到字节数组中
    }

    @Override
    public InputStream getInputStream() throws IOException {
        // 返回缓存的数据
        return new ByteArrayInputStream(requestBody);
    }

    public byte[] getRequestBody() {
        return requestBody;
    }
}

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@WebFilter("/*")  // 这个过滤器会拦截所有请求
public class RequestWrapperFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化操作
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        // 仅对 HttpServletRequest 进行包装
        if (request instanceof HttpServletRequest) {
            CachedBodyHttpServletRequestWrapper wrappedRequest =
                    new CachedBodyHttpServletRequestWrapper((HttpServletRequest) request);
            // 将包装后的请求传递给下一个过滤器
            chain.doFilter(wrappedRequest, response);
        } else {
            // 对非 HttpServletRequest 请求不做任何处理
            chain.doFilter(request, response);
        }
    }

    @Override
    public void destroy() {
        // 销毁操作
    }
}

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class RequestBodyInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws IOException {
        if (request instanceof CachedBodyHttpServletRequestWrapper) {
            // 获取包装后的请求体
            CachedBodyHttpServletRequestWrapper wrappedRequest = (CachedBodyHttpServletRequestWrapper) request;
            String requestBody = new String(wrappedRequest.getRequestBody(), "UTF-8");
            // 打印或处理请求体内容
            System.out.println("Request Body: " + requestBody);

            // 将请求体转换成 Java 对象
            MyRequestObject myRequestObject = new ObjectMapper().readValue(requestBody, MyRequestObject.class);
            System.out.println("Parsed Java Object: " + myRequestObject);
        }

        return true; // 返回 true，表示继续处理请求
    }
}

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean<RequestWrapperFilter> loggingFilter() {
        FilterRegistrationBean<RequestWrapperFilter> registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new RequestWrapperFilter());
        registrationBean.addUrlPatterns("/api/*");  // 这里根据需要配置拦截的 URL
        return registrationBean;
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private RequestBodyInterceptor requestBodyInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(requestBodyInterceptor).addPathPatterns("/api/*");  // 根据需要配置路径
    }
}

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class RequestBodyInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws IOException {
		if (HttpMethod.POST.matches(request.getMethod())) {
 			// 包装请求，使其可以多次读取请求体
            ContentCachingRequestWrapper wrappedRequest = new ContentCachingRequestWrapper(request);

			// 读取请求体，明确指定字符编码为 UTF-8
			String requestBody = new String(wrappedRequest.getContentAsByteArray(), "UTF-8");

            // 打印或处理请求体内容
            System.out.println("Request Body: " + requestBody);

            // 将请求体转换成 Java 对象
            MyRequestObject myRequestObject = new ObjectMapper().readValue(requestBody, MyRequestObject.class);
            System.out.println("Parsed Java Object: " + myRequestObject);
        }

        return true; // 返回 true，表示继续处理请求
    }
}