Spring MVC

Introduction

Modal: Any java class that containing data
View: JSP which is used to display the modal
Controller: A Java class marked with controller annotation which will be used to receive the data, return the modal with result data to the view

Configuration (by xml)

web.xml

To tell where the config file is
Setup the dispatcherServlet so as to send the user request to corresponding controller to handle the request and return the correct view
The output file(war) will be generated based web.xml so as to do deployment

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://xmlns.jcp.org/xml/ns/javaee"
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
	id="WebApp_ID" version="3.1">

	<display-name>spring-mvc-demo</display-name>

	<absolute-ordering />

	<!-- Spring MVC Configs -->

	<!-- Step 1: Configure Spring MVC Dispatcher Servlet -->
	<servlet>
		<servlet-name>dispatcher</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<!-- Spring creates a WebApplicationContext object 
			based on the bean definitions 
		and stores it in the ServletContext of one's web application. -->
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/spring-mvc-demo-servlet.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<!-- Step 2: Set up URL mapping for Spring MVC Dispatcher Servlet -->
	<servlet-mapping>
		<servlet-name>dispatcher</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
	
</web-app>

2. spring-mvc-demo-servlet.xml

To perform component scanning
Allow the support of validation
Define the pattern of getting the view

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
    	http://www.springframework.org/schema/beans/spring-beans.xsd
    	http://www.springframework.org/schema/context
    	http://www.springframework.org/schema/context/spring-context.xsd
    	http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

	<!-- Step 3: Add support for component scanning -->
	<context:component-scan base-package="com.luv2code.springdemo" />

	<!-- Step 4: Add support for conversion, formatting and validation support -->
	<mvc:annotation-driven/>

	<mvc:resources mapping="/resources/**" location="/resources/"></mvc:resources>


	<!-- Step 5: Define Spring MVC view resolver -->
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/view/" />
		<property name="suffix" value=".jsp" />
	</bean>

</beans>

Configuration (By Annotation)

DemoAppConfig.java

package com.luv2code.springdemo.config;
 
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages="com.luv2code.springdemo")
public class DemoAppConfig {
 
	// define a bean for ViewResolver
	@Bean
	public ViewResolver viewResolver() {
		
		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
		
		viewResolver.setPrefix("/WEB-INF/view/");
		viewResolver.setSuffix(".jsp");
		
		return viewResolver;
	}
}

MySpringMvcDispatcherServletInitializer.java

package com.luv2code.springdemo.config;
 
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
 
public class MySpringMvcDispatcherServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
 
	@Override
	protected Class<?>[] getRootConfigClasses() {
		// TODO Auto-generated method stub
		return null;
	}
 
	@Override
	protected Class<?>[] getServletConfigClasses() {
		return new Class[] { DemoAppConfig.class };
	}
 
	@Override
	protected String[] getServletMappings() {
		return new String[] { "/" };
	}
}

Basically, just put the java object into model

    @RequestMapping(value = "/helloform")
    public String formPage(Model model){
        Map<String, String> countryList = new HashMap<>();
        countryList.put("China","CN");
        countryList.put("USA", "US");

        Map<String, String> foodList = new HashMap<>();
        foodList.put("FishBall","Fish Ball");
        foodList.put("ChickenWing", "Chicken Wing");

        model.addAttribute("student", new Student("Peter","Cheng", ""));
        model.addAttribute("countryOption", countryList);
        model.addAttribute("foodOption", foodList);

        return "helloForm";
    }

Validation

To validate whether the user input is matched to the ideal pattern or not
If not , return to the same page with error message

public class Customer {

    @Pattern(regexp = "^/w{5}$", message = "Wrong Pattern")
    private String firstName;

    @NotNull
    @Size(min=1, message = "is required")
    private String lastName;

    @Min(value = 18, message = "must be greater than or equal to 18")
    @Max(value = 30, message = "must be smaller than or equal to 30")
    private Integer age;

    public Customer() {
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

}

Controller

@Controller
@RequestMapping("/customer")
public class CustomerController {

    @InitBinder
    public void initBinder(WebDataBinder dataBinder) {

        // To filter out the space if the user input contains space
        StringTrimmerEditor stringTrimmerEditor = new StringTrimmerEditor(true);

        dataBinder.registerCustomEditor(String.class, stringTrimmerEditor);
    }


    @RequestMapping("/processForm")
    public String processForm(
            @Valid @ModelAttribute("customer") Customer theCustomer,
            BindingResult theBindingResult) {

        // Check whether all of the user input fulfill the pattern or not
        if (theBindingResult.hasErrors()) {
            return "customer-form";
        }
        else {
            return "customer-confirmation";
        }
    }
}

View

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>

<html>

<head>
	<title>Customer Registration Form</title>
	
	<style>
		.error {color:red}
	</style>
</head>
<body>

<i>Fill out the form. Asterisk (*) means required.</i>
<br><br>

	<form:form action="processForm" modelAttribute="customer">
	
		First name: <form:input path="firstName" />
		
		<br><br>
		
		Last name (*): <form:input path="lastName" />
		<form:errors path="lastName" cssClass="error" />
		
		<br><br>

		Age: <form:input path="age" />
		<form:errors path="age" cssClass="error" />

		<br><br>

        CourseCode: <form:input path="courseCode" />
        <form:errors path="courseCode" cssClass="error" />

        <br><br>

		<input type="submit" value="Submit" />
				
	</form:form>

</body>

</html>

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Last updated 2 years ago

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Introduction

Configuration (by xml)

Configuration (By Annotation)

Binding with modal

Validation

Modal

Controller

View