How to use Java to handle form data interaction with front-end and back-end separation?

How to use Java to handle form data interaction with front-end and back-end separation?

With the popularity of front-end and back-end separation architecture, it has become a common way for the front-end to send form data to the back-end through AJAX requests. In this article, we will learn how to use Java to handle form data interaction with front-end and back-end separation. We will use Spring Boot as the backend framework and demonstrate the entire process through a simple example.

First, we need to create a Spring Boot project and add related dependencies. Add the following dependencies in the pom.xml file:

<dependencies>
    <!-- Spring Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
  
    <!-- JSON support -->
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
    </dependency>
</dependencies>

Next, we need to create a Controller to handle POST requests for form data. In this example, we will handle a login form containing a username and password. In the Controller, we use the @RequestBody annotation to receive the JSON data sent by the front end and map it to a custom POJO class.

@RestController
public class UserController {

    @PostMapping("/login")
    public String login(@RequestBody UserRequest userRequest) {
        // 处理登录逻辑
        // 在这里可以调用Service来验证用户和密码

        if (userRequest.getUsername().equals("admin") && userRequest.getPassword().equals("password")) {
            return "登录成功";
        } else {
            return "登录失败";
        }
    }
}

public class UserRequest {
    private String username;
    private String password;

    // Getters and Setters

    // 省略构造函数和其他方法
}

In the above example, the login method of UserController receives a UserRequest object as a parameter. The UserRequest class is a simple POJO class used to save the username and password data sent by the front end.

Next, we need to send a POST request in the front-end code and send the form data to the back-end as JSON data. The following is an example using jQuery:

$.ajax({
    url: "/login",
    type: "POST",
    contentType: "application/json",
    dataType: "json",
    data: JSON.stringify({username: "admin", password: "password"}),
    success: function(response) {
        // 处理后端返回的响应
        console.log(response);
    },
    error: function(xhr, status, error) {
        // 处理请求失败的情况
        console.log(error);
    }
});

In the above example, we use the $.ajax function to send a POST request to the /login path, and Send the username and password as JSON data to the backend. In the success callback function, we can handle the response returned by the backend.

Finally, we need to start the Spring Boot application and verify that the code is working properly. Start the application with the following command:

mvn spring-boot:run

You can then view the network request in your browser's developer tools and examine the response returned by the backend.

Summary:
In this article, we learned how to use Java to handle form data interaction with front-end and back-end separation. We use Spring Boot as the backend framework and demonstrate the entire process with a simple example. By using the @RequestBody annotation to receive the JSON data sent by the front end and mapping it to a custom POJO class, we can easily handle the form data interaction between the front and back ends. This approach makes our applications more flexible and maintainable, and provides a better user experience.

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