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jsp spring

Innocent Iguana answered on April 14, 2024 Popularity 8/10 Helpfulness 5/10

answer jsp spring

jsp spring

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// put your jsp file in /src/main/resources/META-INF/resources/WEB-INF/jsp/sayHello.jsp
// sayHello.jsp, the JSP View file in directory  /src/main/resources/META-INF/resources/WEB-INF/jsp/
<html>
	<head>
		<title> My first HTML Page - JSP</title>
	</head>
	<body>
		<h1>Heading 1</h1>
		<h2>Heading 2</h2>
		Welcome ${name}! 
		This is expression language. this "name" keyword is conveyed through ModelMap
	</body>
</html>

// pom.xml: set up dependency for jsp
<dependency>
	<groupId>org.apache.tomcat.embed</groupId>
	<artifactId>tomcat-embed-jasper</artifactId>
	<scope>provided</scope>
</dependency>

// application.properties: set up view resolver that takes the jsp filename from controller and makes up the filepath of the view
spring.mvc.view.prefix=[/src/main/resources/META-INF/resources]/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
logging.level.org.springframework=info

// Controlller
@Controller
public class SayHelloController {
	@RequestMapping(value = "say-hello-jsp", method = RequestMethod.GET) // value is "/say-hello-jsp" url, and method is GET
	// @RequestParam lets the url take a value as argument to a parameter payload
	// "ModelMap"  helps to pass data from controller to the specified view
	public String sayHelloJsp(@RequestParam(value="name", required = false)String name, ModelMap model){ 
		model.put("name",name); // the name variable now can be accessed in the view with "name" keyword
		return "sayHello"; // the jsp file name
	}

	@RequestMapping(value = "say-hello-jsp", method = RequestMethod.POST) // value is "/say-hello-jsp" url, and method is POST
	public String redirectJsp(){ 
		return "congratulationPage"; // the jsp file name that will appear after submitting a JSP form
	}
}

///// Example 2 (A simple login system)

// login.jsp
<html>
	<head>
		<title>Login Page</title>
	</head>
	<body>
		Welcome to the login page!
		<form method="post">
			Name: <input type="text" name="name">
			Password: <input type="password" name="password">
			<input type="submit">
		</form>
		 
	</body>
</html>


// welcome.jsp
<html>
	<head>
		<title>Welcome Page</title>
	</head>
	<body>
		<div>Welcome to your profile</div>
		<div>Your Name: ${name}</div>
	</body>
</html>

// AuthenticationService.java
@Service
public class AuthenticationService {
	public boolean authenticate(String username, String password) {
		boolean isValidUserName = username.equalsIgnoreCase("john");
		boolean isValidPassword = password.equalsIgnoreCase("secret");
		return isValidUserName && isValidPassword;
	}
}

// LoginController.java

@Controller
public class LoginController {
	private AuthenticationService authenticationService;
	
	public LoginController(AuthenticationService authenticationService) {
		super();
		this.authenticationService = authenticationService;
	}

	@RequestMapping(value="login",method = RequestMethod.GET) // This will open the login page
	public String gotoLoginPage() {
		return "login"; 
	}

	@RequestMapping(value="login",method = RequestMethod.POST) // This will redirect to another page after form submission
	public String gotoWelcomePage(@RequestParam String name, @RequestParam String password, ModelMap model) {
		if(authenticationService.authenticate(name, password)) {
			model.put("name", name);
			return "welcome"; //  will redirect to welcome page for correct authentication 
		}
		return "login"; // will redirect to login page for incorrect authentication
	}
}

Popularity 8/10 Helpfulness 5/10 Language java

Source: Grepper

Tags: java jsp spring

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Contributed on Apr 14 2024

Innocent Iguana

0 Answers Avg Quality 2/10

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