srpingMVC基本使用

1. springMVC基本功能

与servlet技术功能相等,实现表现层开发:

(1) maven坐标导入

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>6.0.11</version>
    </dependency>
    <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>5.0.0</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

(2) 编写表现层

@Controller         // 使用controller定义bean
public class test {

    @GetMapping("/hello")
     @ResponseBody		// 直接返回给浏览器
    public String testMVC(){
        System.out.println("接收到请求");
        return "hello world!";
    }
}

(3) springMVC配置类编写

容器配置:

package com.xjy.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan({"com.xjy.controller"})
public class MvcConfig {
}

定义 Spring MVC应用程序的初始化器:

package com.xjy.config;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.support.AbstractDispatcherServletInitializer;
public class MvcContainerInit extends AbstractDispatcherServletInitializer {
//创建DispatcherServlet的应用程序上下文（ApplicationContext）
    @Override
    protected WebApplicationContext createServletApplicationContext() {
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        ctx.register(MvcConfig.class);
        return ctx;
    }
    //指定DispatcherServlet的映射路径
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
    @Override
    protected WebApplicationContext createRootApplicationContext() {
        return null;
    }
    public WebApplicationContext context(){
        return this.createServletApplicationContext();
    }
}

(4) 部署tomcat访问

注意对应的版本:

部署tomcat程序:

启动程序后浏览器访问:

2. 各种请求方法

get请求

    @GetMapping("/get") // 接受get请求
    @ResponseBody
    public String get(){
        System.out.println("接受到请求");
        return "get";
    }

post请求

        @PostMapping("/post")
    @ResponseBody
    public String post(){
        System.out.println("接受到请求");
        return "post";
    }

put请求

    @PutMapping("/put")
    @ResponseBody
    public String put(){
        System.out.println("接受到请求");
        return "put";
    }

delete请求

    @DeleteMapping("/delete")
    @ResponseBody
    public String delete(){
        System.out.println("接受到请求");
        return "delete";
    }

请求参数提取

@Controller
@RequestMapping("/user")
public class userController {
    @RequestMapping("/hello")
    @ResponseBody
    public String save(){
        System.out.println("接受到请求");
        return "hello word!";
    }
   }

访问:

3. 请求参数接收

(1) param参数接受

直接参数接收:

    @GetMapping("/get")
    @ResponseBody
    public String get(int id){
        System.out.println("接受到请求"+id);
        return "get";
    }

封装到对象中

    @GetMapping("/get")
    @ResponseBody
    public String get(student stu){
        System.out.println("接受到请求"+stu.getName()+stu.getAge());
        return "get";
    }

发送请求:

(2) 路劲参数接收

    @GetMapping("/get/{id}")
    @ResponseBody
    public String get(@PathVariable int id){
        System.out.println("接受到路劲参数:"+id);
        return "get";
    }

发送请求:

集合接受

    @PostMapping("/post")
    @ResponseBody
    public String post(@RequestParam List<Integer> list){
        System.out.println("接受到请求"+list.get(0));
        return "ok";
    }

发送请求:

时间类型接收

    @GetMapping("/get")
    @ResponseBody
    public String get(@DateTimeFormat(pattern = "yyyy-MM-dd") LocalDate date){
        System.out.println("接受到时间参数:"+date);
        return "get";
    }

发送:

json参数接收

maven导包

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.13.3</version>
    </dependency>

开启功能

@Configuration
@ComponentScan({"com.xjy.controller"})
@EnableWebMvc
public class MvcConfig {
}

接收数据

    @PostMapping("/post")
    @ResponseBody
    public String post(@RequestBody student stu){
        System.out.println("接受到请求"+ stu.getName());
        return "{'status','ok'}";
    }

发送数据:

4. 响应数据

方法中直接return

返回json: @ResponseBody 加上注解
@RestController -> @controller + @ResponseBody

5. 全局异常处理

注解需要配包扫描:

@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(Exception.class)
    public String exceptionHandler(Exception ex){
        System.out.println("处理到异常");
        return "err";
    }
}

模拟异常:

6. springMvc拦截器(Interceptor)

自定义拦截:

public class interceptorDo implements HandlerInterceptor {
    @Override // 拦截方法
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("拦截到请求");
        return true;//返回true放行,返回不放行;
    }
    @Override  //资源运行后执行
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }
    @Override  //视图渲染完毕后执行
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

配置拦截器:

@Configuration
@ComponentScan({"com.xjy.controller"})
@EnableWebMvc       
public class MvcConfig implements WebMvcConfigurer {
    @Bean
    public interceptorDo getInteceptor(){
        return new interceptorDo();
    }
    @Autowired
    private interceptorDo interceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
       registry.addInterceptor(interceptor)
               .excludePathPatterns("/long");//过滤登录拦截
    }
}