springmvc依赖注入（springmvc常用5种注解）

初识SpringMVC

实现步骤：

1. 新建一个web项目
2. 导入相关jar包
3. 编写web.xml，注册DispatcherServlet
4. 编写springmvc配置文件
5. 接下来就是去创建对应的控制类 , controller
6. 最后完善前端视图和controller之间的对应
7. 测试运行调试

使用springMVC必须配置的三大件：

处理器映射器、处理器适配器、视图解析器

通常，我们只需要手动配置视图解析器，而处理器映射器和处理器适配器只需要开启注解驱动即可，而省去了大段的xml配置

注解实现SpringMVC

常见注解

@Component组件@Service服务@Controller控制@Respositorydao层

控制器

package com.kuang.controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;//@Controller注解的类会自动添加到Spring上下文中@Controller@RequestMapping("/test2")public class ControllerTest2{//映射访问路径@RequestMapping("/t2")public String index(Model model){//Spring MVC会自动实例化一个Model对象用于向视图中传值model.addAttribute("msg", "ControllerTest2");//返回视图位置return "test";}}

• @Controller是为了让Spring IOC容器初始化时自动扫描到；
• @RequestMapping是为了映射请求路径，这里因为类与方法上都有映射所以访问时应该是/test2/t2；

标准maven依赖

<?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.reliable</groupId>    <artifactId>SpringMVC2</artifactId>    <packaging>pom</packaging>    <version>1.0-SNAPSHOT</version>    <modules>        <module>springmvc-04-controller</module>    </modules>    <dependencies>        <dependency>            <groupId>junit</groupId>            <artifactId>junit</artifactId>            <version>4.12</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-webmvc</artifactId>            <version>5.1.9.RELEASE</version>        </dependency>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>servlet-api</artifactId>            <version>2.5</version>        </dependency>        <dependency>            <groupId>javax.servlet.jsp</groupId>            <artifactId>jsp-api</artifactId>            <version>2.2</version>        </dependency>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>jstl</artifactId>            <version>1.2</version>        </dependency>    </dependencies>    <build>        <resources>            <resource>                <directory>src/main/java</directory>                <includes>                    <include>**/*.properties</include>                    <include>**/*.xml</include>                </includes>                <filtering>false</filtering>            </resource>            <resource>                <directory>src/main/resources</directory>                <includes>                    <include>**/*.properties</include>                    <include>**/*.xml</include>                </includes>                <filtering>false</filtering>            </resource>        </resources>    </build></project>

一、配置pom.xml

<?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">    <parent>        <artifactId>SpringMVC2</artifactId>        <groupId>com.reliable</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>springmvc-04-controller</artifactId>    <dependencies>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>servlet-api</artifactId>            <version>2.5</version>        </dependency>        <dependency>            <groupId>javax.servlet.jsp</groupId>            <artifactId>jsp-api</artifactId>            <version>2.2</version>        </dependency>    </dependencies>    <build>        <resources>            <resource>                <directory>src/main/java</directory>                <includes>                    <include>**/*.properties</include>                    <include>**/*.xml</include>                </includes>                <filtering>false</filtering>            </resource>            <resource>                <directory>src/main/resources</directory>                <includes>                    <include>**/*.properties</include>                    <include>**/*.xml</include>                </includes>                <filtering>false</filtering>            </resource>        </resources>    </build></project>

二、配置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servlet-->    <servlet>        <servlet-name>SpringMVC</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <!--通过初始化参数指定SpringMVC配置文件的位置，进行关联-->        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:springmvc-servlet.xml</param-value>        </init-param>        <!-- 启动顺序，数字越小，启动越早 -->        <load-on-startup>1</load-on-startup>    </servlet>    <!--所有请求都会被springmvc拦截 -->    <servlet-mapping>        <servlet-name>SpringMVC</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping></web-app>

三、配置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        http://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">    <!-- 自动扫描包，让指定包下的注解生效,由IOC容器统一管理 -->    <context:component-scan base-package="com.kuang.controller"/>    <!-- 让Spring MVC不处理静态资源：html 等-->    <mvc:default-servlet-handler/>    <!--    支持mvc注解驱动        在spring中一般采用@RequestMapping注解来完成映射关系        要想使@RequestMapping注解生效        必须向上下文中注册DefaultAnnotationHandlerMapping        和一个AnnotationMethodHandlerAdapter实例        这两个实例分别在类级别和方法级别处理。        而annotation-driven配置帮助我们自动完成上述两个实例的注入。<mvc:annotation-driven /> 完成了映射和适配（支持用注解完成）     -->    <mvc:annotation-driven />    <!-- 视图解析器 -->    <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>

RestFul 风格

概念

Restful就是一个资源定位及资源操作的风格。不是标准也不是协议，只是一种风格。基于这个风格设计的软件可以更简洁，更有层次，更易于实现缓存等机制。

功能

资源：互联网所有的事物都可以被抽象为资源

资源操作：使用POST、DELETE、PUT、GET，使用不同方法对资源进行操作。

分别对应 添加、 删除、修改、查询。

RestFulController(@PathVariable)

package com.kuang.controller;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;@Controllerpublic class RestFulController {//映射访问路径@RequestMapping("/commit/{p1}/{p2}")public String index(@PathVariable int p1, @PathVariable int p2, Model model){int result = p1+p2;//Spring MVC会自动实例化一个Model对象用于向视图中传值model.addAttribute("msg", "结果："+result);//返回视图位置return "test";}//映射访问路径,必须是Get请求@RequestMapping(value = "/hello",method = {RequestMethod.GET})public String index2(Model model){model.addAttribute("msg", "hello!");return "test";}}

使用method属性指定请求类型

用于约束请求的类型，可以收窄请求范围。指定请求谓词的类型如GET, POST, HEAD, OPTIONS, PUT, PATCH, DELETE, TRACE等。

//映射访问路径,必须是Get请求@RequestMapping(value = "/hello",method = {RequestMethod.GET})public String index2(Model model){model.addAttribute("msg", "hello!");return "test";}

除了添加method，还可以使用注解

@GetMapping

@PostMapping

@PutMapping

@DeleteMapping

@PatchMapping

//映射访问路径,必须是Get请求@GetMapping(value = "/hello")public String index2(Model model){model.addAttribute("msg", "hello!");return "test";}