SpringMVC学习（二）——快速搭建SpringMVC开发环境（注解方式）

说明

本文主要是通过注解方式搭建SpringMVC架构，现在通过注解方式搭建框架更加常见以及便捷，文中如果有不妥之处望各位能够批评指正，大家共同进步。
码字不易，转载请注明出处。需要源码请自行下载：https://gitee.com/leo825/spring-framework-learning-example.git

1、工程搭建

可以参考《SpringMVC学习（一）——快速搭建SpringMVC开发环境（非注解方式）》搭建一个非注解型的SpringMVC，注解方式就是在非注解方式的基础之上做的优化。本文也是在这个工程的基础之上做的修改。

2、注解配置

在开启注解的时候遇到几个注解配置：



先说明一下这几个注解的定义，通过他们的定义可以理解他们的用途

2.1、context:annotation-config说明

1、如果想使用@Autowired注解，就必须在Spring容器中声明AutowiredAnnotationBeanPostProcessor的Bean
2、如果想使用@Resource、@PostConstruct、@PreDestroy等注解，就必须在Spring中声明CommonAnnotationBeanPostProcessor的Bean
3、如果想使用@PersistenceContext注解，就必须在Spring中声明PersistenceAnnotationBeanPostProcessor的Bean
4、如果想使用 @Required的注解，就必须在Spring中声明RequiredAnnotationBeanPostProcessor的Bean

AutowiredAnnotationBeanPostProcessor
RequiredAnnotationBeanPostProcessor
CommonAnnotationBeanPostProcessor
PersistenceAnnotationBeanPostProcessor

通过上面的描述我们知道，使用配置就是向Spring容器中注册上面几个Bean，并实现@Autowired、@Resource、@PostConstruct、@PreDestroy、@PersistenceContext、@Required等注解的功能。

2.2、context:component-scan配置说明

下面的是官网上对于这个标签的描述：

Scans the classpath for annotated components that will be auto-registered as
	Spring beans. By default, the Spring-provided @Component, @Repository,
	@Service, and @Controller stereotypes will be detected.

	Note: This tag implies the effects of the 'annotation-config' tag, activating @Required,
	@Autowired, @PostConstruct, @PreDestroy, @Resource, @PersistenceContext and @PersistenceUnit
	annotations in the component classes, which is usually desired for autodetected components
	(without external configuration). Turn off the 'annotation-config' attribute to deactivate
	this default behavior, for example in order to use custom BeanPostProcessor definitions
	for handling those annotations.

大致意思就是说包含要做的事情，同时额外支持@Component、@Repository、@Service、@Controller注解.并且、扫描base-package并且在applicationcontext中注册扫描的beans。因此，如果配置了就不需要再配置

2.3、mvc:annotation-driven配置说明

根据mvc开头能看出来，这个配置是是针对SpringMVC的，配置会向Spring容器中自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter 两个bean，是@Controller分发请求所必须的。并且这个配置提供了数据绑定支持，@NumberFormatannotation支持，@DateTimeFormat支持，@Valid支持，读写XML的支持（JAXB），读写JSON的支持（Jackson非常主要）。

注意：在笔者测试过程中发现配置不是必须的，查了原因这个注解驱动主要是配置RequestMappingHandlerMapping和RequestMappingHandlerAdapter。但是springmvc容器启动是会加载默认的DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter。所以不配置也是不影响项目的启动运行的。但是看源码这个两个默认的实现方法是过时的，因此虽然不影响项目，但是我们一般还是会配置使用新的代替的方法。

这个标签的具体实现类是：

org.springframework.web.servlet.config.AnnotationDrivenBeanDefinitionParser

通过阅读类的注释，可以找到这个类主要向Spring容器中注册了以下Bean实例

RequestMappingHandlerMapping
BeanNameUrlHandlerMapping
RequestMappingHandlerAdapter
HttpRequestHandlerAdapter
SimpleControllerHandlerAdapter
ExceptionHandlerExceptionResolver
ResponseStatusExceptionResolver
DefaultHandlerExceptionResolver

这些Bean的作用依次为：
1、前面两个RequestMappingHandlerMapping、BeanNameUrlHandlerMapping是HandlerMapping接口的实现类，用来处理请求映射的。

• 第一个是处理@RequestMapping注解的。
• 第二个会将Controller类的名称映射为请求的url。

2、中间三个RequestMappingHandlerAdapter、HttpRequestHandlerAdapter、SimpleControllerHandlerAdapter是用来处理请求的。就是调用Controller的那个方法来处理请求。

• 第一个是处理@Controller注解的处理器，支持自定义方法参数和返回值。
• 第二个处理继承HttpRequestHandler的处理器。
• 第三个处理继承自Controller接口的处理器。

3、后面三个是用来处理异常的解析器（自行查看）。
4、除以上之外，此配置还提供以下支持：

• 支持使用ConversionService实例对表单参数进行类型转换；
• 支持使用@NumberFormatannotation、@DateTimeFormat注解完成数据类型的格式化；
• 支持使用@Valid注解对Java bean实例进行JSR 303验证；
• 支持使用@RequestBody和@ResponseBody注解

3、简单代码实现

首先在myspringmvc-servlet.xml中添加上面介绍的注解配置：

    <!-- 配置SpringMVC支持注解，需要放在context:component-scan前面，否则可能会报404-->
    <mvc:annotation-driven></mvc:annotation-driven>
    <!-- 定义项目扫描包的路径，并支持注解例如：@Component、@Repository、@Service、@Controller-->
    <context:component-scan base-package="com.leo"></context:component-scan>

然后开始编写一个Controller，并且添加@Controller注解

@Controller
public class HelloController{

    /**
     * 返回一个ModeAndView
     * @return
     * @throws ServletException
     * @throws IOException
     */
    @RequestMapping(value = "/hello",method = RequestMethod.GET)
    public ModelAndView hello() throws ServletException, IOException {
        System.out.println("使用配置实现 hello controller 跳转到 success");
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("data", "恭喜您，测试成功了");
        modelAndView.setViewName("success");//跳转到/WEB-INF/views/success.jsp
        return modelAndView;
    }

    /**
     * 返回逻辑视图“success”
     * @return
     * @throws ServletException
     * @throws IOException
     */
    @RequestMapping(value = "/hello2",method = RequestMethod.GET)
    public String hello2() throws ServletException, IOException {
        System.out.println("访问了 hello2");
        return "success";
    }

    /**
     * 返回一个字符串
     * @return
     * @throws ServletException
     * @throws IOException
     */
    @RequestMapping(value = "/hello3",method = RequestMethod.GET)
    @ResponseBody
    public String hello3() throws ServletException, IOException {
        System.out.println("访问了 hello3");
        String hello = "你好 SpringMVC";
        return hello;
    }
}

使用 @Autowired注入UserInfoService

@Controller
public class GetUserInfoController {
    @Autowired
    UserInfoService userInfoService;
    
    @RequestMapping("/getUserInfoList1")
    public ModelAndView getUserInfoList1(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        System.out.println("GetUserInfoController获取用户信息");
        ModelAndView modelAndView = new ModelAndView();
        //访问数据库
        List userInfoList = userInfoService.getUserInfoList();
        System.out.println(userInfoList);
        modelAndView.addObject("data", userInfoList);
        modelAndView.setViewName("success");//跳转到/WEB-INF/views/success.jsp
        return modelAndView;
    }
}

如果想使用依赖注入的UserInfoService，首先通过@Service注入到Sping中

@Service
public class UserInfoServiceImpl implements UserInfoService {

    @Autowired
    JdbcTemplate jdbcTemplate;

    @Override
    public void insertUserInfo(UserInfo userInfo) {
        jdbcTemplate.execute("INSERT INTO USER_INFO(NAME,GENDER,AGE,REMARKS) VALUES('" + userInfo.getName() + "','" + userInfo.getGender() + "','" + userInfo.getAge() + "','" + userInfo.getRemarks() + "')");
    }

    @Override
    public void deleteUserInfo(Integer id) {
        DBUtil.getJdbcTemple().execute("DELETE FROM USER_INFO WHERE ID = " + id);
    }

    @Override
    public void updateUserInfo(Integer id, UserInfo newUserInfo) {
        jdbcTemplate.update("UPDATE USER_INFO SET NAME=?, GENDER=?, AGE=? ,REMARKS=? WHERE ID=?", new Object[]{
                newUserInfo.getName(),
                newUserInfo.getGender(),
                newUserInfo.getAge(),
                newUserInfo.getRemarks(),
                id
        });
    }

    @Override
    public List<UserInfo> getUserInfoList() {
        List<UserInfo> userInfos = new ArrayList<>();
        List<Map<String, Object>> results = jdbcTemplate.queryForList("SELECT * FROM USER_INFO");
        for (Map obj : results) {
            UserInfo userInfo = new UserInfo();
            userInfo.setId((Integer) obj.get("ID"));
            userInfo.setName((String) obj.get("NAME"));
            userInfo.setGender("0".equals((String) obj.get("GENDER")) ? "女" : "男");
            userInfo.setAge((String) obj.get("AGE"));
            userInfo.setRemarks((String) obj.get("REMARKS"));
            userInfos.add(userInfo);
        }
        return userInfos;
    }
}

4、文件上传下载实现

4.1 文件上传jar包依赖

首先，如果没有添加jar包依赖的在pom.xml中添加依赖

        <!-- SpirngMVC支持文件上传的工具包 -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.3</version>
        </dependency>

4.2 在Spring中添加Bean配置

其次，需要在myspringmvc-servlet.xml配置文件中添加Bean支持

    
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        
        <property name="defaultEncoding" value="utf-8">property>
        
        <property name="maxUploadSize" value="1048576">property>
    bean>

4.3 文件上传实现

通过以上的配置值就可以使用MutipartFile直接接收文件了

    /**
     * 文件上传
     *
     * @param multipartFil
     * @param request
     * @return
     * @throws IOException
     */
    @RequestMapping(value = "/upload", method = RequestMethod.POST)
    public String upload(@RequestParam(value = "file") MultipartFile multipartFil, HttpServletRequest request) throws IOException {
        if (!multipartFil.isEmpty()) {
            //文件标签名
            System.out.println(multipartFil.getName());
            //上传文件名称
            System.out.println(multipartFil.getOriginalFilename());
            //文件大小
            System.out.println(multipartFil.getSize());
            //上传文件的类型
            System.out.println(multipartFil.getContentType());

            String fileDirStr = request.getServletContext().getRealPath("/uploadFile");
            String filename = multipartFil.getOriginalFilename();
            System.out.println(fileDirStr);
            File fileDir = new File(fileDirStr);
            if (!fileDir.exists()) {
                fileDir.mkdirs();
            }
            File file1 = new File(fileDir, filename);
            multipartFil.transferTo(file1);
        }
        return "success";
    }

前端的测试代码如下：

<form action="${pageContext.request.contextPath}/upload"
      enctype="multipart/form-data"
      method="post">
    <input type="file" name="file" value="请选择需要上传的文件" /><br>
    <input type="submit" value="提交">
form>

4.4 文件下载实现

文件下载的方式也有很多，这里提供一下三种测试方法：

    /**
     * 下载文件：
     * 通过Spring提供的这种对象，这种下载具有局限性，文件太大会导致内存溢出异常
     *
     * @param request
     * @param filename
     * @return
     * @throws IOException
     */
    @RequestMapping(value = "/download", method = RequestMethod.GET)
    public ResponseEntity<byte[]> download(HttpServletRequest request, @RequestParam String filename) throws IOException {
        String fileDirStr = request.getServletContext().getRealPath("/uploadFile");
        File file = new File(fileDirStr, filename);
        byte[] body = FileUtils.readFileToByteArray(file);
        //设置下载名称，否则乱码
        String downloadFilename = new String(file.getName().getBytes("utf-8"), "iso-8859-1");
        HttpHeaders httpHeaders = new HttpHeaders();
        //设置文件类型
        httpHeaders.add("Content-Disposition", "attchement;filename=" + downloadFilename);

        ResponseEntity responseEntity = new ResponseEntity(body, httpHeaders, HttpStatus.OK);
        return responseEntity;
    }

    /**
     * 使用字节流直接输出，实现类似上面
     *
     * @param request
     * @param response
     * @param filename
     */
    @RequestMapping(value = "/download2", method = RequestMethod.GET)
    public void download2(HttpServletRequest request, HttpServletResponse response, @RequestParam String filename) throws IOException {
        //获取主机文件
        String fileDirStr = request.getServletContext().getRealPath("/uploadFile");
        File file = new File(fileDirStr, filename);
        byte[] outByte = FileUtils.readFileToByteArray(file);
        //设置下载名称，否则乱码
        String downloadFilename = new String(file.getName().getBytes("utf-8"), "iso-8859-1");
        response.setHeader("Content-Disposition", "attchement;filename=" + downloadFilename);
        response.getOutputStream().write(outByte);
        response.getOutputStream().close();
    }

    /**
     * 普通的输出输出流下载
     *
     * @param request
     * @param response
     * @param filename
     * @throws IOException
     */
    @RequestMapping(value = "/download3", method = RequestMethod.GET)
    public void download3(HttpServletRequest request, HttpServletResponse response, @RequestParam String filename) throws IOException {
        //获取主机文件
        String fileDirStr = request.getServletContext().getRealPath("/uploadFile");
        File file = new File(fileDirStr, filename);
        InputStream inputStream = new FileInputStream(file);

        //设置下载名称，否则乱码
        String downloadFilename = new String(file.getName().getBytes("utf-8"), "iso-8859-1");
        response.setHeader("Content-Disposition", "attchement;filename=" + downloadFilename);
        OutputStream os = response.getOutputStream();
        byte[] bf = new byte[2048];
        int len;
        while ((len = inputStream.read(bf)) > 0) {
            os.write(bf, 0, len);
        }
        os.close();
        inputStream.close();
    }

5、拦截器配置

5.1 拦截器代码实现

首先，编写两个拦截器继承自HandlerInterceptorAdapter
第一个拦截器：

public class HandlerInterceptor1 extends HandlerInterceptorAdapter {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("HandlerInterceptor1 preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("HandlerInterceptor1 postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("HandlerInterceptor1 afterCompletion");
    }
}

第二个拦截器：

public class HandlerInterceptor2 extends HandlerInterceptorAdapter {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("HandlerInterceptor2 preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("HandlerInterceptor2 postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("HandlerInterceptor2 afterCompletion");
    }
}

5.2 拦截器配置实现

编写完上面的拦截器代码之后，需要将Bean实例注入到Spring中

    
    <mvc:interceptors>
        <bean class="com.leo.interceptor.HandlerInterceptor1">bean>
        <bean class="com.leo.interceptor.HandlerInterceptor2">bean>
    mvc:interceptors>

访问：http://localhost:8080/springmvc/hello
执行情况如下日志所示：

HandlerInterceptor1 preHandle
HandlerInterceptor2 preHandle
HelloController.handlerAllException
HandlerInterceptor2 afterCompletion
HandlerInterceptor1 afterCompletion
HandlerInterceptor1 preHandle
HandlerInterceptor2 preHandle
使用配置实现 hello controller 跳转到 success
HandlerInterceptor2 postHandle
HandlerInterceptor1 postHandle
HandlerInterceptor2 afterCompletion
HandlerInterceptor1 afterCompletion

5.3 排除拦截器配置实现

需要在myspringmvc-servlet.xml配置文件中添加如下配置信息：

    
    <mvc:interceptors>
        <mvc:interceptor>
            
            <mvc:mapping path="/springmvc/*"/>
            
            <mvc:exclude-mapping path="/springmvc/hello">mvc:exclude-mapping>
            <bean class="com.leo.interceptor.HandlerInterceptor1">bean>
        mvc:interceptor>
        <mvc:interceptor>
        	
            <mvc:mapping path="/**"/>
            <bean class="com.leo.interceptor.HandlerInterceptor2">bean>
        mvc:interceptor>
    mvc:interceptors>

配置后，再访问：http://localhost:8080/springmvc/hello
控制台输出的日志为如下：

HandlerInterceptor2 preHandle
使用配置实现 hello controller 跳转到 success
HandlerInterceptor2 postHandle
HandlerInterceptor2 afterCompletion

想了解过滤器和拦截器区别的可以参考：《SpringMVC中过滤器和拦截器的区别》

6、统一异常配置

@ControllerAdvice 注解修饰可以处理所有的Controller的异常

@ControllerAdvice
public class HandlerException {
    @ExceptionHandler
    public ModelAndView handlerAllException(Exception e) {
        ModelAndView mv = new ModelAndView();
        mv.addObject("exceptionMsg", e.getMessage());
        mv.setViewName("error");
        System.out.println("HelloController.handlerAllException");
        return mv;
    }
    @ExceptionHandler(value = {ArithmeticException.class})
    public ModelAndView handlerArithmeticException(Exception e) {
        ModelAndView mv = new ModelAndView();
        mv.addObject("exceptionMsg", e.getMessage());
        mv.setViewName("error");
        System.out.println("HelloController.handlerArithmeticException");
        return mv;
    }
}

当然也可以通过在myspringmvc-servlet.xml配置文件中添加Bean支持实现

    
    <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
        
        <property name="exceptionAttribute" value="ex">property>
        <property name="exceptionMappings">
            <props>
                <prop key="java.lang.ArrayIndexOutOfBoundsException">errorprop>
            props>
        property>
    bean>

7、日志集成

本章节介绍的是集成log4j2日志框架，首先pom中配置依赖jar

        
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-apiartifactId>
            <version>2.11.2version>
        dependency>
        <dependency>
            <groupId>org.apache.logging.log4jgroupId>
            <artifactId>log4j-coreartifactId>
            <version>2.11.2version>
        dependency>

然后在相应的文件目录下编写log4j.xml模板文件，笔者的在resources下

<Configuration status="ERROR" monitorInterval="30">
    <Properties>
        
        <Property name="LOG_HOME">/root/bubble/logsProperty>
        <property name="ERROR_LOG_FILE_NAME">/root/bubble/logsproperty>
    Properties>
    <Appenders>
        
        <Console name="Console" target="SYSTEM_OUT">
            
            <ThresholdFilter level="TRACE" onMatch="ACCEPT" onMismatch="DENY" />
            
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level %logger{36}:%L [%t] - %msg%n" />
        Console>
        
        <RollingFile name="RollingFileInfo" fileName="${LOG_HOME}/search.log" filePattern="${LOG_HOME}/$${date:yyyy-MM}/search-%d{yyyy-MM-dd}-%i.log">
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY" />
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level %logger{36}:%L [%t] - %msg%n" />
            
            <Policies>
                
                
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
                
                <SizeBasedTriggeringPolicy size="100 MB" />
            Policies>
            
            <DefaultRolloverStrategy max="100" />
        RollingFile>
        <RollingFile name="RollingFileError"
                     fileName="${ERROR_LOG_FILE_NAME}/search-error.log"
                     filePattern="${ERROR_LOG_FILE_NAME}/$${date:yyyy-MM}/search-error-%d{yyyy-MM-dd}.log">
            <ThresholdFilter level="ERROR" onMatch="ACCEPT" onMismatch="DENY" />
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level %logger{36}:%L [%t] - %msg%n" />
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true" />
            Policies>
            <DefaultRolloverStrategy max="100" />
        RollingFile>
    Appenders>
    
    <Loggers>
        
        <logger name="org.springframework" level="INFO">logger>
        
        
        <root level="all">
            <appender-ref ref="Console" />
            <appender-ref ref="RollingFileInfo" />
            <appender-ref ref="RollingFileError" />
        root>
    Loggers>
Configuration>

然后在web.xml文件中，将日志文件配置到上下文中

    
    <context-param>
        <param-name>log4jConfigurationparam-name>
        <param-value>classpath:log4j2.xmlparam-value>
    context-param>

完成以上配置就已经集成了log4j2框架。开始测试：

@Controller
@RequestMapping("/log")
public class LoggerRecordController {
    //获取日志
    private static final Logger LOGGER = LogManager.getLogger();

    @Autowired
    UserInfoService userInfoService;

    @RequestMapping("/testLog1")
    @ResponseBody
    public ModelAndView testLog1(@RequestParam("username") String name) {
        long startTime = System.currentTimeMillis();
        ModelAndView modelAndView = new ModelAndView();
        //访问数据库
        List userInfoList = userInfoService.getUserInfoList();
        LOGGER.info(userInfoList);
        modelAndView.addObject("data", userInfoList);
        modelAndView.setViewName("success");//跳转到/WEB-INF/views/success.jsp
        LOGGER.info("获取name=" + name + "接口耗时：" + (System.currentTimeMillis() - startTime) + "ms");
        return modelAndView;

    }
}

测试结果，如下所示：

2020-02-09 20:15:59.608 INFO  com.leo.controller.LoggerRecordController:38 [http-apr-8080-exec-7] - [UserInfo{id=3, name='晓玲', gender='女', age='22', remarks='工程师'}, UserInfo{id=4, name='晓玲', gender='女', age='24', remarks='工程师'}]
2020-02-09 20:15:59.631 INFO  com.leo.controller.LoggerRecordController:41 [http-apr-8080-exec-7] - 获取name=leo825接口耗时：39ms