# springMVC-注解配置

**Repository Path**: liubin2000/springMVC-firstDemo

## Basic Information

- **Project Name**: springMVC-注解配置
- **Description**: 完全使用配置类和注解来代替web.xml和spring MVC.xml进行配置的入门项目
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-10-16
- **Last Updated**: 2021-10-16

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Spring-MVC-完全注解式配置



## 前言：本文是springMVC的入门级案例，采用完全注解式开发

> versions：
>
> ​	java - 1.8
>
> ​	tomcat - 8.5
>
> ​	spring - 5.3.1
>
> gitee地址：



## 一、项目依赖

+ pom.xml

```xml
<!-- 指定jdk的编译版本 -->
<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.compilerVersion>1.8</maven.compiler.compilerVersion>
</properties>
<!-- 默认打成war包 -->
<packaging>war</packaging>

<dependencies>
    <!-- SpringMVC-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.1</version>
    </dependency>

    <!-- 日志-->
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.3</version>
    </dependency>

    <!-- ServletAPI-->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <!--  provided表明该包只在编译和测试的时候用 -->
        <scope>provided</scope>
    </dependency>

    <!-- Spring5和Thymeleaf整合包-->
    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf-spring5</artifactId>
        <version>3.0.12.RELEASE</version>
    </dependency>

    <!-- Json转换 -->
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.12.4</version>
    </dependency>

    <!-- 文件上传组件 -->
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.1</version>
    </dependency>
</dependencies>
```



## 二、使用Java配置类代替web.xml 和 springMVC.xml

### 1. src文件目录

``` 
|-- src
    |-- main
    |   |-- java
    |   |   |-- com
    |   |       |-- lb
    |   |           |-- mvc
    |   |               |-- config
    |   |               |   |-- SpringConfig.java
    |   |               |   |-- WebConfig.java
    |   |               |   |-- WebInit.java
    |   |               |-- controller
    |   |               |   |-- ExceptionController.java
    |   |               |   |-- TestController.java
    |   |               |-- interceptors
    |   |                   |-- MyInterceptor.java
    |   |-- resources
    |   |-- webapp
    |       |-- WEB-INF
    |           |-- templates
    |               |-- error.html
    |               |-- index.html
    |               |-- success.html
    |-- test
        |-- java
```

### 2.**WebInit类**

> 因其继承于**AbstractAnnotationConfigDispatcherServletInitializer**类，因此Tomcat将会自动加载这个类

``` java
public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {
    /**
     * 指定spring的配置类
     *
     * @return
     */
    @Override
    protected Class<?>[] getRootConfigClasses() {

        return new Class[]{SpringConfig.class};
    }

    /**
     * 指定SpringMVC的配置类
     *
     * @return
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }

    /**
     * 指定DispatcherServlet的映射规则, <url-pattren></url-pattren>
     *
     * @return
     */
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    /**
     * 注册过滤器
     *
     * @return
     */
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter("UTF-8", true);
        HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();

        return new Filter[]{characterEncodingFilter, hiddenHttpMethodFilter};
    }
}
```

### 3. SpringConfig类

> 最基础的mvc项目不用配置该类，仅做个标识

``` java
@Configuration
public class SpringConfig {
}
```

### 4. WebConfig类

> ```
> /**
>  * 该类用于代替SpringMVC的配置文件，可以实现如下功能的配置
>  * 1. 注解扫描      2. 视图解析器        3. view-controller  4. default-servlet-handler
>  * 5. mvc注解驱动   6. 文件上传解析器     7. 异常处理         8.拦截器
>  */
> ```

``` java
@Configuration
@ComponentScan(basePackages = {"com.lb.mvc"}) // 1. 注解扫描
@EnableWebMvc // 5. mvc注解驱动
public class WebConfig implements WebMvcConfigurer {

    //4. default-servlet-handler
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    // 8.拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor())
                .addPathPatterns("/**"); // 拦截所有路径
    }

    // 3. view-controller
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("index");
    }

    // 6. 文件上传解析器
    @Bean
    public CommonsMultipartResolver multipartResolver() {
       return new CommonsMultipartResolver();
    }

    //7. 异常处理 , 也可以另外写类加上@ControllerAdvice
    /*@Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
        Properties properties = new Properties();
        properties.setProperty("ArithmeticException", "error");
        exceptionResolver.setExceptionMappings(properties);
        exceptionResolver.setExceptionAttribute("exception");
        resolvers.add(exceptionResolver);
    }*/

    /**
     * 配置模板解析器
     *
     * @return
     */
    @Bean
    public ITemplateResolver templateResolver() {
        WebApplicationContext webApplicationContext = ContextLoader.getCurrentWebApplicationContext();
        //ServletContextTemplateResolver 需要一个 ServletContext 作为构造参数，可以通过 WebApplicationContext 获得
        ServletContextTemplateResolver templateResolver =
                new ServletContextTemplateResolver(webApplicationContext.getServletContext());

        templateResolver.setPrefix("/WEB-INF/templates/");  // 视图前缀
        templateResolver.setSuffix(".html");    // 视图后缀
        templateResolver.setCharacterEncoding("UTF-8");
        templateResolver.setTemplateMode(TemplateMode.HTML);
        return templateResolver;
    }

    /**
     * 配置模板引擎
     *
     * @param templateResolver 模板解析器
     * @return
     */
    @Bean
    public SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver);
        return templateEngine;
    }

    /**
     * 配置视图解析器, thymeleaf
     *
     * @param templateEngine 模板引擎
     * @return
     */
    @Bean
    public ViewResolver viewResolver(SpringTemplateEngine templateEngine) {
        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setOrder(1);
        viewResolver.setCharacterEncoding("UTF-8");
        viewResolver.setTemplateEngine(templateEngine);
        return viewResolver;
    }
}
```

### 5. MyInterceptor类

``` java
public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("拦截器配置成功");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}
```

### 6. ExceptionController类

> 异常处理类

``` java
@ControllerAdvice
public class ExceptionController {

    @ExceptionHandler(value = {ArithmeticException.class, NullPointerException.class})
    public String test(Exception e, Model model) {
        model.addAttribute("exception", e); // 将异常类共享到request域中
        return "error";	// 转发到error视图
    }
}
```

### 7. TestController类

``` java
@Controller
public class TestController {

    @RequestMapping("/testArithmeticException")
    public String testArithmeticException() {
        int i = 10 / 0;
        return "success";
    }

    @RequestMapping("/testNullPointerException")
    public String testNullPointerException() {
        Object o = null;
        System.out.println(o.hashCode());
        return "success";
    }
}
```

### 8. index、success、error页面

``` html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>index</title>
</head>
<body>
<h1>首页</h1>
</body>
</html>
```
``` html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>success</title>
</head>
<body>
success
</body>
</html>
```
``` html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>error</title>
</head>
<body>
<p th:text="${exception}"></p>
</body>
</html>
```

<font color="red" size="5px">别气馁，马上就要成功了，还差最后一步！</font>



## 三、Idea集成Tomcat

完整过程: https://www.jianshu.com/p/7e026b76424e