学习：狂神

SpringMVC

-------->> 导jar包
		<dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
        </dependency>
        
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
      </dependency>

• 注册bean

注册HandlerMapping，HandlerAdapter，配置视图ViewResolver，注册执行类/hello

<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>

<!--    无法使用中文注释时,可尝试修改字符集UTF-8为GBK（或UTF8）
        xml文件中文注释报错解决办法:https://blog.csdn.net/kejijun/article/details/108228535
-->

<!-- 配置视图 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/jsp/"/>
    <property name="suffix" value=".jsp"/>
</bean>

<bean id="/hello" class="com.controller.HelloController"/>

• 创建Servlet容器配置

DispatcherServlet

<servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc-serlvet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

• 实现Controller接口:创建控制器类

public class HelloController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        
        ModelAndView mv=new ModelAndView();
        System.out.println("CCCCCCCCCCCC");
        mv.addObject("msg","msg返回信息到jsp页面");
        mv.setViewName("packge");
        return mv;
    }
}

注解入门

• 配置

<context:component-scan base-package="com.controller"/>
<!-- 资源过滤 -->
<mvc:default-servlet-handler/>
<!--mvc注解驱动 -->
<mvc:annotation-driven/>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/jsp/"/>
    <property name="suffix" value=".jsp"/>
</bean>

• 创建控制器类

@Controller
@RequestMapping("/big")
public class HelloMaking {
    @RequestMapping("/hello")
    public String hello(Model model){
       // 封装数据
        model.addAttribute("msg","return msg to hello");
        return "hello";  //会被视图解析器处理 拼接/WEB-INF/jsp/hello.jsp
    }


    @RequestMapping("/save")
    @ResponseBody						//@ResponseBody设置当前控制器方法响应内容为当前返回值，无需(视图解析器)解析
    public String save(){
        System.out.println("user save ...");
        return "{'module':'springmvc'}"; 		//使用@ResponseBody直接返回字符串		
    }
}

@Controller

名称	@Controller
类型	类注解
位置	SpringMVC控制器类定义上方
作用	设定SpringMVC的核心控制器bean

@RequestMapping

名称	@RequestMapping
类型	类注解或方法注解
位置	SpringMVC控制器类或方法定义上方
作用	设置当前控制器方法请求访问路径
相关属性	value(默认)，请求访问路径

@ResponseBody

名称	@ResponseBody
类型	类注解或方法注解
位置	SpringMVC控制器类或方法定义上方
作用	设置当前控制器方法响应内容为当前返回值，无需解析

RestFul风格

http://localhost/test/save?id=1
http://localhost/test/update
http://localhost/test/delete?id=1

• 传统模式 URI 和 RESTful 风格对比

【1】查询

查询	传统	REST	REST 后台接收
查询所有	localhost:8080/employee/list	localhost:8080/employees	@RequestMapping(value = “/employees”, method = RequestMethod.GET)
查询单个	localhost:8080/employee/list?id=1	localhost:8080/employees/1	@RequestMapping(value = “/employees/{id}”, method = RequestMethod.GET) @ResponseBody public Employee queryById(@PathVariable Long id) {}

​ 【2】添加

添加	传统	REST	REST 后台接收
添加	localhost:8080/employee/add	localhost:8080/employees	@RequestMapping(value = “/employees”, method = RequestMethod.POST) public Employee add(@ModelAttribute(“emp”) Employee employee) {}

【3】修改

修改	传统	REST	REST 后台接收
修改	ocalhost:8080/employee/update	localhost:8080/employees	@RequestMapping(value = “/employees”, method = RequestMethod.PUT) public Employee update(@ModelAttribute(“emp”) Employee employee) {}

【4】删除

查询	传统	REST	REST 后台接收
删除	localhost:8080/employee/delete	localhost:8080//employees/{id}	@RequestMapping(value = “/employees/{id}”, method = RequestMethod.DELETE) @ResponseBody public JsonResult delete(@PathVariable Long id) {}

• 原生

@RequestMapping("/save")            //原生：http://localhost:8080/test/save?a=2&b=3
public String save(int a,int b,Model model){
    int res=a+b;
    model.addAttribute("msg","save结果为："+res);
    return "hello";
}

• RestFul

@RequestMapping("/save/{a}/{b}")      //REST:http://localhost:8080/test/save/a/b
public String save2(@PathVariable int a, @PathVariable int b, Model model){
    int res=a+b;
    model.addAttribute("msg","save2结果为："+res);
    return "hello";
}

• RestFul请求方式

//    @RequestMapping(value = "/save/{a}/{b}",method = RequestMethod.POST)
 @PostMapping("/save/{a}/{b}")           //通过请求方式 @GetMapping     @DeleteMapping
 public String save3(@PathVariable int a, @PathVariable int b, Model model){
        int res=a+b;
        model.addAttribute("msg","save3结果为："+res);
        return "hello";
}