Review the traditional annotation SpringMVC architecture

1. The pom

<! -- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.2.2. RELEASE</version>
</dependency>

<! -- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.2. RELEASE</version>
</dependency>
<! -- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
    <scope>provided</scope>
</dependency>
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2. The new package in the Java directory and AbstractAnnotationConfigDispatcherServletInitializer implementation class

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class SpringMvcInit extends AbstractAnnotationConfigDispatcherServletInitializer{

	@Override
	protectedClass<? >[] getRootConfigClasses() {return null;
	}

	@Override
	protectedClass<? >[] getServletConfigClasses() {return null;
	}

	@Override
	protected String[] getServletMappings() {
		return new String[] {"/"}; }}Copy the code

Explain why use implementation AbstractAnnotationConfigDispatcherServletInitializer to initialize the DispatcherServlet:

In the Servlet3.0 environment, the container will be in the classpath lookup javax.mail. Servlet. ServletContainerInitializer interface classes, if found, you can use it to configure the servlet container. Spring provides the implementation of this interface, called SpringServletContainerInitializer, this class, in turn, will find implementation WebApplicationInitializer classes and the configuration tasks to them. Spring3.2 based implementation, introduces a convenient WebApplicationInitializer called AbstractAnnotationConfigDispatcherServletInitializer, When our class extends the AbstractAnnotationConfigDispatcherServletInitializer and deploy it to Servlet3.0 container, the container automatically discover it, and use it to configure the Servlet context.

3. Create RootConfig

import org.springframework.context.annotation.Configuration;

@Configuration
public class RootConfig {}Copy the code

@Override
protectedClass<? >[] getRootConfigClasses() {return new Class[] {RootConfig.class};
}
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4. Create the WebConfig configuration

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@EnableWebMvc // Start springMVC component driver < MVC :annotation-driven>
@ComponentScan("com.demo")
public class WebConfig implements WebMvcConfigurer {}Copy the code

@Override
protectedClass<? >[] getServletConfigClasses() {return new Class[] {WebConfig.class};
}
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5. The controller

@RequestMapping("/hello")
@RestController
public class HelloController {

	@GetMapping
	public String hello(a) {
		
		return "hello"; }}Copy the code

7. Test

8. Return objects

public class User {

	private int id;

	private String name;
	

	public User(int id, String name) {
		super(a);this.id = id;
		this.name = name;
	}

	public int getId(a) {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName(a) {
		return name;
	}

	public void setName(String name) {
		this.name = name; }}Copy the code

@RequestMapping("/hello")
@RestController
public class HelloController {

	@GetMapping
	public String hello(a) {
		
		return "hello";
	}
	
	@GetMapping("/user")
	public User getUser(a) {
		return new User(30."luopeng"); }}Copy the code

9. The test

The solution was

<! -- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.10.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.1</version>
</dependency>
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11. The test