1, Introduction to nginx

Nginx (engine x) is a high-performance HTTP and reverse proxy web server, which is characterized by less memory and strong concurrency. In fact, nginx performs better in the same type of web server.

Nginx is specially developed for performance optimization. Performance is its most important consideration. In fact, it pays great attention to efficiency and can withstand the test of high load. Some reports show that it can support up to 50000 concurrent connections.

2, Reverse proxy

1. Forward agency

Configure a proxy server on the client (browser) to access the Internet through the proxy server.

2. Reverse proxy

We only need to send the request to the reverse proxy server. The reverse proxy server selects the target server, obtains the data, and then returns it to the client. At this time, the reverse proxy server and the target server are external servers, exposing the proxy server address and hiding the real server IP address.

3, Load balancing

Increase the number of servers, and then distribute the requests to each server. Instead of concentrating the original requests on a single server, distribute them to multiple servers, and distribute the load to different servers, which is what we call load balancing.

4, Dynamic and static separation

In order to speed up the parsing speed of the website, dynamic pages and static pages can be parsed by different servers to speed up the parsing speed. Reduce the pressure of the original single server.

5, nginx common commands

1. Prerequisite for using nginx operation command: nginx directory must be

2. Check the version number of nginx

nginx -v

3. Start nginx

nginx

4. Turn off nginx

nginx -s stop

5. Reload nginx

nginx -s reload

6, Configuration file for nginx (nginx.conf)

The nginx configuration file consists of three parts

1. Global block

The content from the configuration file to the events block mainly sets some configuration instructions that affect the overall operation of the nginx server.

For example: Worker_ processes 1; worker_ The larger the processes value, the more concurrent processing can be supported.

2.events block

The instructions involved in the events block mainly affect the network connection between the nginx server and the user.  
For example: worker_connection 1024; Maximum number of connections supported.

3.http block

The most frequent part of nginx server configuration, http block can also include http global block and server block.

7, nginx configuration image access path

Upload the image file to the server D:/images, and then access it through the IP address / upload / plus the image name.

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       80;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        #Access path splicing upload accesses a picture under the local absolute path 
        location /upload/ {
        alias D:/images/;
        autoindex on;
        }

        location / {
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }

    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

}

Configure nginx Conf remember to restart the server. The effect is shown in the figure:

8, java background code

/**
 * File upload
 */
@RestController
public class FileController {

    @PostMapping(value = "/fileUpload")
    public String fileUpload(@RequestParam(value = "file") MultipartFile file) {
        if (file.isEmpty()) {
            System.out.println("Please select a picture");
        }
        String fileName = file.getOriginalFilename();  // file name
        String suffixName = fileName.substring(fileName.lastIndexOf("."));  // Suffix
        String filePath = "D:/images/"; // Uploaded path
        fileName = UUID.randomUUID() + suffixName; // New file name
        File dest = new File(filePath + fileName);
        if (!dest.getParentFile().exists()) {
            dest.getParentFile().mkdirs();
        }
        try {
            file.transferTo(dest);
        } catch (IOException e) {
            e.printStackTrace();
        }
        //Return picture name
        return fileName;
    }
}

Here, upload the image to the D:/images folder. Because nginx is configured earlier, I test it locally. You can access it directly by using the image name returned by localhost/upload / +.

If you want to access through the project address plus the port number, you can configure a resource mapping path.

/**
 * Resource mapping path
 */
@Configuration
public class MyWebMvcConfig implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/upload/**").addResourceLocations("file:D:/images/");
    }
}

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