Detailed explanation of how to process user data in SpringBoot controller

1. Get request parameters

1.1 Get query parameters

In GET requests, we usually pass data by querying parameters. Can be used@RequestParamAnnotation to receive these parameters.

import ;
import ;
import ;

@RestController
public class UserController {

    @GetMapping("/users")
    public String getUsers(@RequestParam String name, @RequestParam int age) {
        return "User name: " + name + ", Age: " + age;
    }
}

1.2 Get path parameters

For parameters that need to be passed in the URL, you can use@PathVariableAnnotation.

@GetMapping("/users/{id}")
public String getUserById(@PathVariable Long id) {
    return "User ID: " + id;
}

2. Process form submission

2.1 Processing form data

When processing form data submitted by a POST request, you can use@ModelAttributeAnnotation binds form data to an object.

import ;
import ;
import ;

@RestController
public class UserController {

    @PostMapping("/users")
    public String createUser(@ModelAttribute User user) {
        // Logic to save user information to the database        return "User created: " + user;
    }
}

CorrespondingUserkind:

public class User {
    private String name;
    private String email;

    // Getters and Setters
}

3. Process JSON data

3.1 Receive JSON data

For data submitted in JSON format, you can use@RequestBodyAnnotation binds it to an object.

import ;
import ;
import ;

@RestController
public class UserController {

    @PostMapping("/users/json")
    public String createUser(@RequestBody User user) {
        // Logic to save user information to the database        return "User created: " + user;
    }
}

4. Return JSON data

The Spring Boot controller can easily return JSON data, just return an object, and Spring Boot will automatically convert it to JSON format.

import ;
import ;

@RestController
public class UserController {

    @GetMapping("/users/json")
    public User getUserJson() {
        User user = new User();
        ("John Doe");
        ("john@");
        return user;
    }
}

5. Process file upload

5.1 Single file upload

Can be used@RequestParamAnnotation receives uploaded files.

import ;
import ;
import ;
import ;

@RestController
public class FileController {

    @PostMapping("/upload")
    public String uploadFile(@RequestParam("file") MultipartFile file) {
        if (()) {
            return "File is empty";
        }
        // Logic of saving files        return "File uploaded successfully: " + ();
    }
}

5.2 Multi-file upload

Supporting multiple file uploads is also very simple, just put@RequestParamThe parameter type is set toMultipartFile[]。

@PostMapping("/upload/multiple")
public String uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {
    for (MultipartFile file : files) {
        if (()) {
            return "One or more files are empty";
        }
        // Logic of saving files    }
    return "Files uploaded successfully";
}

6. Summary

Through this article, you have mastered a variety of ways to process user data in Spring Boot controllers, including obtaining request parameters, processing form submissions, receiving and returning JSON data, and processing file uploads. These skills are the basis for building RESTful APIs and web applications. In actual development, flexibly using these technologies can meet various business needs and provide efficient and flexible interface services. I hope this article can help you become more skillful in Spring Boot development.

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