The method of using the jQuery framework in the Java class library to verify the form verification
The method of using the jQuery framework in the Java class library to verify the form verification
Introduction:
Form verification is one of the common requirements in web development. It is used to ensure that the data entered by the user before submitting the form data meets specific rules or requirements.JQuery is a popular JavaScript library that provides many simple and easy -to -use methods to handle various operations in the webpage.In the Java class library, the JQuery framework is combined with a format verification, and a strong verification function can be achieved in a simple and clear way.
step:
The following is the steps to verify the form verification of the JQuery framework in the Java class library:
1. Introduce the jQuery library in the project: First of all, you need to introduce the jquery library file into the project.You can download the latest jquery library file from the official website (https://jquery.com/) and place it in the appropriate position of the project.For example, place jquery files in the "Web/JS" directory of the project.
2. Create a form page: In Java, you can use template engines such as JSP, Thymeleaf to generate form pages.In the form page, the jQuery library file needs to be introduced.You can use the following code to introduce the jquery library file into the page:
html
<script src="/js/jquery.min.js"></script>
3. Write Form Verification Logic: In the form page, use the Jquery framework method to write form verification logic.The following is a simple example code that is used to verify whether the user name and password meet the requirements:
html
<script>
$(document).ready(function(){
$('form').submit(function(event){
// Cancel the default submission of the form
event.preventDefault();
// Get the value of the user name and password input box
var username = $('#username').val();
var password = $('#password').val();
// Perform table verification
if (username.length === 0) {
alert ('Username cannot be empty!');
} else if (password.length < 6) {
alert ('password length should not be less than 6 digits!');
} else {
// Data verification passes, submit forms
$('form').unbind('submit').submit();
}
});
});
</script>
In the above code, first use the `$ (document) .Ready (function () {})` to ensure that the page executes the code after loading.Then use `$ ('form'). Submit (function (event) {}` to bind the submission event of the form, and use the default submission of the form.#Username '). Val () `and` $ ('#password '). Val () `to obtain the value of the user name and password input box.The error message pops up; if the verification is passed, the submission event is unbundered and the submission of the form is used to use `$ ('form'). Submit ()`.
4. Revolution of the back -end table. In the Java library, in addition to using the jQuery framework at the front end to verify the form, it also needs to be verified at the back end to ensure that the input data meets the requirements.You can use the verification framework in the Java library, such as Hibernate Validator, Spring Validator, etc.According to the specific framework and needs, write the corresponding back -end form verification code.
Summarize:
By using the jQuery framework in the Java library, the format verification function can be easily implemented.According to the above steps, introduce the jQuery library file and write verification logic, which can achieve simple and powerful form verification functions.At the same time, in order to ensure the security and effectiveness of the data entered by the user, it is necessary to verify at the back end.
Example code:
Below is a complete use of the jQuery framework in the Java class library to verify the example code for form verification:
@Controller
@RequestMapping("/user")
public class UserController {
@PostMapping("/login")
public String login(@Valid User user, BindingResult bindingResult) {
if (bindingResult.hasErrors()) {
return "login";
}
// Other processing logic
return "redirect:/home";
}
}
html
<!DOCTYPE html>
<html>
<head>
<Title> Login Page </Title>
<script src="/js/jquery.min.js"></script>
<script>
$(document).ready(function(){
$('form').submit(function(event){
event.preventDefault();
var username = $('#username').val();
var password = $('#password').val();
if (username.length === 0) {
alert ('Username cannot be empty!');
} else if (password.length < 6) {
alert ('password length should not be less than 6 digits!');
} else {
$('form').unbind('submit').submit();
}
});
});
</script>
</head>
<body>
<form action="/user/login" method="post">
<div>
<laabel for = "username"> Username: </label>
<input type="text" id="username" name="username">
</div>
<div>
<Label for = "Password"> Password: </label>
<input type="password" id="password" name="password">
</div>
<input type = "submit" value = "login">
</form>
</body>
</html>
In the above code, the `Login` method in the` UserController` class receives a `User` object, and use the@Valid` annotation to verify it.If the verification fails, return the login page; if the verification is passed, other processing logic will be performed and redo -to the homepage.The form in the front page uses the jQuery framework to verify. If the verification is not approved, the error message is popped up using the `Alert ()" method.
