springboot整合springmvc

1、创建springboot项目，勾选Spring web

1. 当前springboot选择的是2.6.13版本，jdk1.8
2. 尽量选2.几的springboot

2、在pom.xml中导入相应的坐标

<dependency>
          <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
</dependency>         

3、配置application.yml，按需配置，可选

server:
  port: 8080

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: myuser
    password: mypassword
    driver-class-name: com.mysql.cj.jdbc.Driver

  servlet:
    multipart:
      max-file-size: 10MB # 设置单个文件最大上传大小
      max-request-size: 50MB # 设置请求的最大总数据大小
      enabled: true # 开启文件上传支持

  format:
    date-time-patterns:
      - yyyy-MM-dd HH:mm:ss # 日期时间格式
      -
  mvc:
    static-path-pattern: /static/** # 指定静态资源的访问路径模式
    resources:
      static-locations: file:/path/to/your/static/files/ # 指定静态资源文件的存储位置

    view:
      prefix: /WEB-INF/views/ # view前缀
      suffix: .jsp # view后缀，如：.jsp

4、创建controller包，报下新建UserController进行测试

package com.example.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {

    @GetMapping("hello")
    public String test(){
        return "hello ssm";
    }
}

//访问http://localhost:8080/user/hello，返回hello ssm即为测试成功

5、访问静态资源

默认的静态资源路径为：

classpath:/META-INF/resources/

classpath:/resources/

classpath:/static/（一般放置在这个文件夹下）

classpath:/public/

只要静态资源放在这些目录中任何一个，SpringMVC都会帮我们处理

6、相关注解

1、@RequestMapping

1. 用于Controller类、类中方法上，用来处理请求地址映射的注解
2. @RequestMapping(value = "/login",produces = "application/json;charset=utf-8", method = RequestMethod.GET)
   1. value：url的值，
   2. method：提交方式 ，get或者post
   3. produces：指定响应体返回类型和编码
3. @GetMapping，与@RequestMapping作用一致，但指定必须为get请求，且只能用在类上
4. @PostMapping，与@RequestMapping作用一致，但指定必须为post请求，且只能用在类上

2、@RequestParam

1. 用于Controller类的方法参数前，如4中test()如果有参数，即可使用test(@RequestParam String name)
2. @RequestParam(value="username", required=true, defaultValue="zhang") String name)
   1. value表示 入参的请求参数名字，前端传过来的必须和这个名称一样
   2. required默认值是true，意思为该参数必传
   3. defaultValue表示默认值，当前设定为zhang
3. 注解可用于map与对象：test(@RequestParam Map query）、test(@RequestParam User user）

3、@RequestBody

1. 用于Controller类的方法上，效果是接收JSON数据

4、@PathVariable

1. 拥有绑定url中的占位符的。例如：url中有/delete/{id}，{id}就是占位符
2. deleteById(@PathVariable ("id") String uid）：将占位符{id}的值绑定给了形参uid

5、@ResponseBody

1. 用于Controller类的方法上，效果是返回JSON数据给前端。

2. 返回值一般写AjaxResult

3. AjaxResult工具类

   package com.pj.util;
   
   import java.io.Serializable;
   import java.util.List;
   
   
   /**
    * ajax请求返回Json格式数据的封装 
    */
   public class AjaxJson implements Serializable{
   
   	private static final long serialVersionUID = 1L;	// 序列化版本号
   	
   	public static final int CODE_SUCCESS = 200;			// 成功状态码
   	public static final int CODE_ERROR = 500;			// 错误状态码
   	public static final int CODE_WARNING = 501;			// 警告状态码
   	public static final int CODE_NOT_JUR = 403;			// 无权限状态码
   	public static final int CODE_NOT_LOGIN = 401;		// 未登录状态码
   	public static final int CODE_INVALID_REQUEST = 400;	// 无效请求状态码
   
   	public int code; 	// 状态码
   	public String msg; 	// 描述信息 
   	public Object data; // 携带对象
   	public Long dataCount;	// 数据总数，用于分页 
   	
   	/**
   	 * 返回code  
   	 * @return
   	 */
   	public int getCode() {
   		return this.code;
   	}
   
   	/**
   	 * 给msg赋值，连缀风格
   	 */
   	public AjaxJson setMsg(String msg) {
   		this.msg = msg;
   		return this;
   	}
   	public String getMsg() {
   		return this.msg;
   	}
   
   	/**
   	 * 给data赋值，连缀风格
   	 */
   	public AjaxJson setData(Object data) {
   		this.data = data;
   		return this;
   	}
   
   	/**
   	 * 将data还原为指定类型并返回
   	 */
   	@SuppressWarnings("unchecked")
   	public <T> T getData(Class<T> cs) {
   		return (T) data;
   	}
   	
   	// ============================  构建  ================================== 
   	
   	public AjaxJson(int code, String msg, Object data, Long dataCount) {
   		this.code = code;
   		this.msg = msg;
   		this.data = data;
   		this.dataCount = dataCount;
   	}
   	
   	// 返回成功
   	public static AjaxJson getSuccess() {
   		return new AjaxJson(CODE_SUCCESS, "ok", null, null);
   	}
   	public static AjaxJson getSuccess(String msg) {
   		return new AjaxJson(CODE_SUCCESS, msg, null, null);
   	}
   	public static AjaxJson getSuccess(String msg, Object data) {
   		return new AjaxJson(CODE_SUCCESS, msg, data, null);
   	}
   	public static AjaxJson getSuccessData(Object data) {
   		return new AjaxJson(CODE_SUCCESS, "ok", data, null);
   	}
   	public static AjaxJson getSuccessArray(Object... data) {
   		return new AjaxJson(CODE_SUCCESS, "ok", data, null);
   	}
   	
   	// 返回失败
   	public static AjaxJson getError() {
   		return new AjaxJson(CODE_ERROR, "error", null, null);
   	}
   	public static AjaxJson getError(String msg) {
   		return new AjaxJson(CODE_ERROR, msg, null, null);
   	}
   	
   	// 返回警告 
   	public static AjaxJson getWarning() {
   		return new AjaxJson(CODE_ERROR, "warning", null, null);
   	}
   	public static AjaxJson getWarning(String msg) {
   		return new AjaxJson(CODE_WARNING, msg, null, null);
   	}
   	
   	// 返回未登录
   	public static AjaxJson getNotLogin() {
   		return new AjaxJson(CODE_NOT_LOGIN, "未登录，请登录后再次访问", null, null);
   	}
   	
   	// 返回没有权限的 
   	public static AjaxJson getNotJur(String msg) {
   		return new AjaxJson(CODE_NOT_JUR, msg, null, null);
   	}
   	
   	// 返回一个自定义状态码的
   	public static AjaxJson get(int code, String msg){
   		return new AjaxJson(code, msg, null, null);
   	}
   	
   	// 返回分页和数据的
   	public static AjaxJson getPageData(Long dataCount, Object data){
   		return new AjaxJson(CODE_SUCCESS, "ok", data, dataCount);
   	}
   	
   	// 返回，根据受影响行数的(大于0=ok，小于0=error)
   	public static AjaxJson getByLine(int line){
   		if(line > 0){
   			return getSuccess("ok", line);
   		}
   		return getError("error").setData(line); 
   	}
   
   	// 返回，根据布尔值来确定最终结果的  (true=ok，false=error)
   	public static AjaxJson getByBoolean(boolean b){
   		return b ? getSuccess("ok") : getError("error"); 
   	}
   	
   	/* (non-Javadoc)
   	 * @see java.lang.Object#toString()
   	 */
   	@SuppressWarnings("rawtypes")
   	@Override
   	public String toString() {
   		String data_string = null;
   		if(data == null){
   			
   		} else if(data instanceof List){
   			data_string = "List(length=" + ((List)data).size() + ")";
   		} else {
   			data_string = data.toString();
   		}
   		return "{"
   				+ "\"code\": " + this.getCode()
   				+ ", \"msg\": \"" + this.getMsg() + "\""
   				+ ", \"data\": " + data_string
   				+ ", \"dataCount\": " + dataCount
   				+ "}";
   	}
   	
   }

7、请求转发和重定向

1、forward请求转发

/*** 使用forward关键字进行请求转发 * "forward:转发的JSP路径"，不走视图解析器了，所以需要编写完整的路径 * @return * @throws Exception */
        @RequestMapping("/delete")
        public String delete() throws Exception {
            System.out.println("delete方法执行了...");
            // return "forward:/WEB-INF/pages/success.jsp"; 
            return "forward:/user/findAll";
        }

2、redirect重定向

  /*** 重定向 * @return * @throws Exception */
    @RequestMapping("/count")
    public String count() throws Exception {
        System.out.println("count方法执行了...");
        return "redirect:/add.jsp";
        // return "redirect:/user/findAll"; }
    }

8、拦截器

1、新建Interceptor包，包下新建MyHandlerInterceptor文件

package com.example.Interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyHandlerInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("Pre Handle: " + request.getMethod() + " " + request.getRequestURI());
        System.out.println("在控制器方法调用之前执行");
        return true; // 继续处理请求
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("Post Handle: " + request.getRequestURI());
        System.out.println("在控制器方法调用之后执行，但在视图渲染之前");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("After Completion: " + request.getRequestURI());
        System.out.println("在整个请求完成后执行，无论是否出现异常");
    }
}

2、XML 配置

<?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:aop="http://www.springframework.org/schema/aop"
       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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd">


    <mvc:interceptors>
        <bean class="com.example.Interceptor.MyHandlerInterceptor" />
    </mvc:interceptors>
</beans>

3、新建config包，包下新建WebMvcConfigurer文件

package com.example.config;

import com.example.Interceptor.MyHandlerInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyHandlerInterceptor())
                .addPathPatterns("/**") // 指定拦截器的应用路径
                .excludePathPatterns("/resources/**", "/static/**"); // 排除静态资源
    }
}

拦截器参考链接

springboot整合springmvc参考链接