In the previous chapter, we briefly introduced the source code demo of the interceptor. , there is no exception when getting get parameter in interceptor, but after reading body content in input stream in interceptor, @ RequestBody annotation parameter in controller cannot get content

The following describes the source code to solve this problem.

Test source

The directory structure of interceptor ﹣ demo2 of springboot project is as follows:

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>interceptor_demo2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>interceptor_demo2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Configuration file application.properties, only configure the web server port

server.port=8090

Custom interceptor TestInterceptor

package com.example.interceptor_demo2.interceptor;


import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class TestInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("uri="+request.getRequestURI());
        try {
            RequestWrapper requestWrapper = new RequestWrapper(request);
            String body = requestWrapper.getBody();
            System.out.println("Interceptor gets body content:"+body);
        }catch (Exception e){
            e.printStackTrace();
        }
        return true;
    }
}

Register interceptor WebConfigurer

package com.example.interceptor_demo2.interceptor;

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

@Configuration
public class WebConfigurer implements WebMvcConfigurer {

    @Autowired
    private TestInterceptor loginInterceptor;

    /**
     * This method is used to configure static resources, such as html, js, css, etc.
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
    }

    /**
     * This method is used to register interceptors. The interceptors written by ourselves need to be registered here to take effect.
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // addPathPatterns("/ * *") means to intercept all requests.
        // excludePathPatterns("/login", "/register") means that in addition to login and registration, login registration does not need to be accessed.
        registry.addInterceptor(loginInterceptor).addPathPatterns("/**");
    }
}

RequestWrapper

package com.example.interceptor_demo2.interceptor;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;

public class RequestWrapper extends HttpServletRequestWrapper {
    private final String body;

    public RequestWrapper(HttpServletRequest request) {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        InputStream inputStream = null;
        try {
            inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {

        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        body = stringBuilder.toString();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        ServletInputStream servletInputStream = new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }
            @Override
            public boolean isReady() {
                return false;
            }
            @Override
            public void setReadListener(ReadListener readListener) {
            }
            @Override
            public int read() throws IOException {
                return byteArrayInputStream.read();
            }
        };
        return servletInputStream;

    }

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

    public String getBody() {
        return this.body;
    }

}

Filter ChannelFilter

package com.example.interceptor_demo2.interceptor;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@WebFilter(urlPatterns = "/*",filterName = "channelFilter")
public class ChannelFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if(servletRequest instanceof HttpServletRequest) {
            requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
        }
        if(requestWrapper == null) {
            System.out.println("servletRequest");
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            System.out.println("requestWrapper");
            filterChain.doFilter(requestWrapper, servletResponse);
        }
    }

    @Override
    public void destroy() {

    }
}

Test class TestController

package com.example.interceptor_demo2.controller;

import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @RequestMapping("/test")
    public String test(@RequestBody String paramsJson){
        System.out.println("paramsJson"+paramsJson);
        return "controller@RequestBody Get parameter content:" + paramsJson;
    }

}

Start class InterceptorDemoApplication

package com.example.interceptor_demo2;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
//Registered filter annotations
@ServletComponentScan
public class InterceptorDemo2Application {

    public static void main(String[] args) {
        SpringApplication.run(InterceptorDemo2Application.class, args);
    }

}

test

Using postman test, send post request body as json content {"key": "123"}. If postman is not installed and there is no other test post request tool Click here to download

Source code

Links: https://pan.baidu.com/s/1knR0rWTR3c3dP7CDJjYG3A
Extraction code: 7x0j