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SpringMVC中常用注解(案例讲解)

安七月读书 2022-03-17 阅读 34

SpringMVC中常用注解

  • RequestParam
  • RequestBody
  • PathVaribale
    • 先了解下REST 风格 URL
  • RequestHeader
  • CookieValue
  • ModelAttribute
    • 修饰的方法有返回值
    • 修饰的方法没有返回值
  • SessionAttribute

RequestParam

说明

代码示例

jsp代码:

<%--
  Created by IntelliJ IDEA.
  User: Keafmd
  Date: 2021/1/25
  Time: 10:48
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>常用注解</title>
</head>
<body>

    <!-- requestParams 注解的使用 -->
    <a href="anno/testRequestParam?name=keafmd">RequestParam</a><br/>

</body>
</html>
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控制器代码:

package com.Keafmd.controller;

import com.Keafmd.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.bind.support.SessionStatus;

import java.util.Date;
import java.util.Map;

/**
 * Keafmd
 *
 * @ClassName: AnnoConteoller
 * @Description: 注解的控制器
 * @author: 牛哄哄的柯南
 * @date: 2021-01-25 10:50
 */
@Controller
@RequestMapping("/anno")
public class AnnoConteoller {

    /**
     * requestParams 注解的使用
     * @param username
     * @return
     */
    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(value="name") String username){
        // @RequestParam(value="name") 必须传name,required:请求参数中是否必须提供此参数,默认值是true,必须提供
        // 获得当前类名
        String clazz = Thread.currentThread().getStackTrace()[1].getClassName();
        // 获得当前方法名
        String method = Thread.currentThread().getStackTrace()[1].getMethodName();

        System.out.println("执行了:"+clazz+" - "+method);
        System.out.println("username:"+username);
        return "success";
    }

}
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输出结果:

执行了:com.Keafmd.controller.AnnoConteoller - testRequestParam
username:keafmd
12

RequestBody

说明

代码示例

jsp代码:

<form action="anno/testRequestBody" method="post">
        用户姓名:<input type="text" name="uname" /><br/>
        用户年龄:<input type="text" name="age" /><br/>
        用户生日:<input type="text" name="birthday" /><br/>
        <input type="submit" value="提交">
</form>
123456

控制器代码:

/**
* 获取到请求体的内容 RequestBody
 */

@RequestMapping("/testRequestBody")
public String testRequestBody(@RequestBody String body){
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);
    System.out.println("body:"+body);
    return "success";
}
1234567891011

输出结果:

执行了: testRequestBody
body:uname=Keafmd&age=21&birthday=2000-01-01
12

PathVaribale

先了解下REST 风格 URL

说明

代码示例

jsp代码:

<a href="anno/testPathVariable/10">testPathVariable</a><br/>
1

控制器代码:

/**
* PathVariable
* @param id
* @return
*/
@RequestMapping("/testPathVariable/{sid}")
public String testPathVariable(@PathVariable(name="sid") String id){
   // 获得当前方法名
   String method = Thread.currentThread().getStackTrace()[1].getMethodName();
   System.out.println("执行了:"+" "+method);
   System.out.println("id:"+id);
   return "success";
}
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输出结果:

执行了: testPathVariable
id:10
12

RequestHeader

说明

代码示例

jsp代码:

<a href="anno/testRequestHeader">testRequestHeader</a><br/>
1

控制器代码:

/**
* RequestHeader获取请求头的值  不常用
* @param head
* @return
*/
@RequestMapping("/testRequestHeader")
public String testRequestHeader(@RequestHeader(value = "Accept") String head){
   // 获得当前方法名
   String method = Thread.currentThread().getStackTrace()[1].getMethodName();
   System.out.println("执行了:"+" "+method);

   System.out.println("head:"+head);
   return "success";
}
1234567891011121314

输出结果:

执行了: testRequestHeader
head:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
12

CookieValue

说明

代码示例

jsp代码:

<a href="anno/testCookieValue">testCookValue</a><br/>
1

控制器代码:

/**
 * CookieValue 不常用
 * @param cookievalue
 * @return
 */
@RequestMapping("/testCookieValue")
public String testCookieValue(@CookieValue(value = "JSESSIONID") String cookievalue){
    // 获得当前方法名
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);

    System.out.println("cookievalue:"+cookievalue);
    return "success";
}
1234567891011121314

输出结果:

执行了: testCookieValue
cookievalue:DCCFE2C1F975AC04D4F55973ADA5C89C
12

ModelAttribute

说明

代码示例

jsp代码:

<form action="anno/testModelAttribute" method="post">
	用户姓名:<input type="text" name="uname" /><br/>
    用户年龄:<input type="text" name="age" /><br/>
    <input type="submit" value="提交">
</form>
12345

修饰的方法有返回值

控制器代码:

/**
 * ModelAttribute
 * @return
 */

@RequestMapping("/testModelAttribute")
public String testModelAttribute(User user){
    // 获得当前方法名
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);
    System.out.println(user);
    return "success";
}

//有返回值
@ModelAttribute
public User showUser(String uname){
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);
    User user = new User();
    user.setUname(uname);
    user.setAge(20);
    user.setBirthday(new Date());
    return user;
}
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输出结果:

执行了: testModelAttribute
User{uname='牛哄哄的柯南', age=21, birthday=Mon Jan 25 19:34:46 CST 2021}
12

修饰的方法没有返回值

控制器代码:

/**
 * ModelAttribute
 * @return
 */

@RequestMapping("/testModelAttribute")
public String testModelAttribute(@ModelAttribute("abc")User user){
    // 获得当前方法名
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);
    System.out.println(user);
    return "success";
}

//无返回值
@ModelAttribute
public void showUser(String uname, Map<String,User> map){
    String method = Thread.currentThread().getStackTrace()[1].getMethodName();
    System.out.println("执行了:"+" "+method);
    User user = new User();
    user.setUname(uname);
    user.setAge(20);
    user.setBirthday(new Date());
    map.put("abc",user);
}
12345678910111213141516171819202122232425

输出结果:

执行了: testModelAttribute
User{uname='牛哄哄的柯南', age=21, birthday=Mon Jan 25 19:32:20 CST 2021}
12

SessionAttribute

说明

代码示例

jsp代码:

<a href="anno/testSessionAttributes">存入SessionAttributes</a><br/>
<a href="anno/getSessionAttributes">获取SessionAttributes</a><br/>
<a href="anno/delSessionAttributes">清除SessionAttributes</a><br/>
123

控制器代码:

package com.Keafmd.controller;

import com.Keafmd.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.bind.support.SessionStatus;

import java.util.Date;
import java.util.Map;

/**
 * Keafmd
 *
 * @ClassName: AnnoConteoller
 * @Description: 注解的控制器
 * @author: 牛哄哄的柯南
 * @date: 2021-01-25 10:50
 */
@Controller
@RequestMapping("/anno")
@SessionAttributes(value = {"msg"}) //把msg=牛哄哄的柯南存到session域中
public class AnnoConteoller {

    /**
     * SessionAttributes注解,存入msg
     * @return
     */
    @RequestMapping("/testSessionAttributes")
    public String testSessionAttributes(Model model){
        // 获得当前方法名
        String method = Thread.currentThread().getStackTrace()[1].getMethodName();
        System.out.println("执行了:"+" "+method);

        //底层会存到Request域中
        model.addAttribute("msg","牛哄哄的柯南");

        return "success";
    }

    /**
     * 获取
     * @param modelMap
     * @return
     */
    @RequestMapping("/getSessionAttributes")
    public String getSessionAttributes(ModelMap modelMap){
        // 获得当前方法名
        String method = Thread.currentThread().getStackTrace()[1].getMethodName();
        System.out.println("执行了:"+" "+method);

        //从session域中取出来
        String msg = (String)modelMap.get("msg");
        System.out.println(msg);
        return "success";
    }

    /**
     * 清除
     * @param sessionStatus
     * @return
     */
    @RequestMapping("/delSessionAttributes")
    public String delSessionAttributes(SessionStatus sessionStatus) {
        // 获得当前方法名
        String method = Thread.currentThread().getStackTrace()[1].getMethodName();
        System.out.println("执行了:"+" "+method);

        //从session域中清除
        sessionStatus.setComplete();
        return "success";
    }


}

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输出结果:

执行了: testSessionAttributes
执行了: getSessionAttributes
牛哄哄的柯南
执行了: delSessionAttributes
执行了: getSessionAttributes
null
123456

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