SpringMVC之Controller和@RequestMapping

1. 使用Controller接口1.1 导入依赖<dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>5.1.9.RELEASE</vers

Java追求者

586人浏览 · 2021-05-10 16:13:53

Java追求者 · 2021-05-10 16:13:53 发布

1. 使用Controller接口

1.1 导入依赖

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.1.9.RELEASE</version>
    </dependency>
    <!--Servlet依赖-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>
    <!--jsp的依赖-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
        <version>2.3.3</version>
    </dependency>
    <!--JSTL表达式依赖-->
    <dependency>
        <groupId>javax.servlet.jsp.jstl</groupId>
        <artifactId>jstl-api</artifactId>
        <version>1.2</version>
    </dependency>
</dependencies>

1.2 编写web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!--1.注册DispatcherServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--关联-个springmvc的配置文件: [servlet-name ] -servlet.xml-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--启动级别-1-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!--/匹配所有的请求: (不包括.jsp)-->
    <!--/*匹配所有的请求; (包括.jsp)-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

1.3 编写springmvc-servlet.xml

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--视图解析器:DispatcherServlet给他的ModeLAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>
    <bean name="/t1" class="com.test.controller.HelloController"/>
</beans>

1.4 实现Controller接口

//注意:这里我们先导入Controller接口
public class HelloController implements Controller {
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        //ModeLAndView模型和视图
        ModelAndView mv = new ModelAndView();
        //封装对象，放在ModeLAndView中Model
        mv.addObject("msg", "HelloSpringMVC!");
        //.封装要跳转的视图，放在ModeLAndView中
        mv.setViewName("hello"); //: /WEB- INF/jsp/hello. jsp .
        return mv;
    }
}

1.5 启动Tomcat，测试

浏览器输入：http://localhost:8080/t1

小结：

实现接口Controller定义控制器是较老的办法
缺点是:一个控制器中只有一个方法，如果要多个方法则需要定义多个Controller; 定义的方式比较麻烦;

2. 使用@Controller注解

2.1 导入依赖

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.1.9.RELEASE</version>
    </dependency>
    <!--Servlet依赖-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>
    <!--jsp的依赖-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
        <version>2.3.3</version>
    </dependency>
    <!--JSTL表达式依赖-->
    <dependency>
        <groupId>javax.servlet.jsp.jstl</groupId>
        <artifactId>jstl-api</artifactId>
        <version>1.2</version>
    </dependency>
</dependencies>

2.2 编写web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!--1.注册DispatcherServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--关联-个springmvc的配置文件: [servlet-name ] -servlet.xml-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!--启动级别-1-->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <!--/匹配所有的请求: (不包括.jsp)-->
    <!--/*匹配所有的请求; (包括.jsp)-->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

2.3 编写springmvc-servlet.xml

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <context:component-scan base-package="com.test.controller"/>
    <!--视图解析器:DispatcherServlet给他的ModeLAndView-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver">
        <!--前缀-->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!--后缀-->
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

2.4 使用@Controller注解

@Controller
public class HelloController2 {
    @RequestMapping("/t2")
    public String hello(Model model) {
        model.addAttribute("msg","HelloController2");
        return "hello";
    }

    @RequestMapping("/t3")
    public String hello2(Model model) {
        model.addAttribute("msg","t3");
        return "hello";
    }
}

2.5 启动Tomcat，测试

浏览器输入：
http://localhost:8080/t2
http://localhost:8080/t3

3. @RequestMapping

@RequestMapping注解用于映射ur|到控制器类或一个特定的处理程序方法。可用于类或方法上。
在类上，表示类中的所有响应请求的方法都是以该地址作为父路径。

@Controller
@RequestMapping("/c1")
public class HelloController2 {
    @RequestMapping("/t2")
    public String hello(Model model) {
        model.addAttribute("msg","HelloController2");
        return "hello";
    }

    @RequestMapping("/t3")
    public String hello2(Model model) {
        model.addAttribute("msg","t3");
        return "hello";
    }
}