使用java代码代替xml实现SSM教程

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.xiao.ssm</groupId>
    <artifactId>SSM-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <tomcat.version>2.2</tomcat.version>
        <webserver.port>8888</webserver.port>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <!--引入springMVC依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.12.RELEASE</version>
        </dependency>
        <!--引入servlet依赖-->
        <!--scope作用域：
           1.compile，默认的scope（作用域），表示 dependency 都可以在生命周期中使用。而且，这些dependencies 会传递到依赖的项目中。适用于所有阶段，会随着项目一起发布
           2.provided,跟compile相似，但是表明了dependency 由JDK或者容器提供，例如Servlet AP和一些Java EE APIs。这个scope 只能作用在编译和测试时，同时没有传递性
           3.runtime,表示dependency不作用在编译时，但会作用在运行和测试时，如JDBC驱动，适用运行和测试阶段
           4.test,表示dependency作用在测试时，不作用在运行时。 只在测试时使用，用于编译和运行测试代码。不会随项目发布
           5.system,跟provided 相似，但是在系统中要以外部JAR包的形式提供，maven不会在repository查找它
        -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!-- tomcat7插件 -->
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>${tomcat.version}</version>
                <configuration>
                    <port>${webserver.port}</port>
                    <path>/${project.artifactId}</path>
                    <uriEncoding>${project.build.sourceEncoding}</uriEncoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <id>central</id>
            <url>https://maven.aliyun.com/nexus/content/repositories/central</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>central</id>
            <url>https://maven.aliyun.com/nexus/content/repositories/central</url>
        </pluginRepository>
    </pluginRepositories>
</project>

package com.xiao.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;
/**
 * @author xiaoss
 * @Configuration注解标识该类是一个配置类，作用类似于：applicationContext.xml文件
 * @ComponentScan注解标识配置包扫描，useDefaultFilters表示使用默认的过滤器，excludeFilters里面的配置表示除去Controller里面的注解，
 * 即项目启动时候，spring容器只扫描除了Controller类之外的所有bean
 * @date 2021年10月29日 16:43
 */
@Configuration
@ComponentScan(basePackages = "com.xiao",useDefaultFilters = true,
        excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Controller.class)})
public class SpringConfig {
}

package com.xiao.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
/**
 * @author xiaoss
 * @date 2021年10月29日 16:56
 */
@Configuration
//@ComponentScan(basePackages = "com.xiao",useDefaultFilters = true,
//        excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,classes = Controller.class)})
@ComponentScan(basePackages = "com.xiao")
public class SpringMVCConfig extends WebMvcConfigurationSupport {
    /**
     * 配置静态资源过滤，相当于   <mvc:resources mapping="/**" location="/"></>
     * @param registry
     */
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/js/**").addResourceLocations("classpath:/");
    }
    /**
     * 配置视图解析器
     * @param registry
     */
    @Override
    protected void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/jsp/",".jsp");
    }
    
    /**
     * 路径映射
     * @param registry
     */
    @Override
    protected void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/hello3").setViewName("hello");
    }
    
    /**
     * json转换配置
     * @param converters
     */
    @Override
    protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter converter=new FastJsonHttpMessageConverter();
        converter.setDefaultCharset(Charset.forName("UTF-8"));
        FastJsonConfig fastJsonConfig=new FastJsonConfig();
        fastJsonConfig.setCharset(Charset.forName("UTF-8"));
        converter.setFastJsonConfig(fastJsonConfig);
        converters.add(converter);
    }
}

package com.xiao.config;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
/**
 * @author xiaoss
 * @date 2021年10月29日 17:13
 */
public class WebInit implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        //首先来加载SpringMVC的配置文件
        AnnotationConfigWebApplicationContext ctx=new AnnotationConfigWebApplicationContext();
        ctx.register(SpringMVCConfig.class);
        //添加DispatcherServlet
        ServletRegistration.Dynamic springmvc=servletContext.addServlet("springmvc",new DispatcherServlet(ctx));
        //给DispatcherServlet添加路径映射
        springmvc.addMapping("/");
        //给DispatcherServlet添加启动时机
        springmvc.setLoadOnStartup(1);
    }
}

package com.xiao.control;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * @author xiaoss
 * @date 2021年10月29日 17:00
 */
@RestController
public class HelloController {
    @GetMapping("/hello")
    public String hello(){
        return "hello";
    }
}

package com.xiao.control;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
/**
 * @author xiaoss
 * @date 2021年10月29日 22:17
 */
@Controller
public class HelloController2 {
    @GetMapping("hello2")
    public String hello2(){
        return "hello";
    }
}