基于springmvc之常用注解,操作傳入?yún)?shù)

更新時(shí)間：2021年09月09日 10:12:55 作者：Code神之手

這篇文章主要介紹了springmvc之常用注解，操作傳入?yún)?shù)方式，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教

springmvc常用注解,操作傳入?yún)?shù)

@RequestParam

一般用于jsp參數(shù)名和后臺(tái)方法參數(shù)指定，對(duì)應(yīng)

/*
    * value=name 當(dāng)jsp的參數(shù)和方法上的參數(shù)對(duì)應(yīng)不上，可以指明
    * required() default true;默認(rèn)true   有參數(shù)則必須傳
    * */
    public String testRequestParam(@RequestParam(name = "name",required = false) String username){
        System.out.println("執(zhí)行了..........");
        System.out.println(username);
        return "success";
    }

<body>
    <a href="anno/testRequestParam" rel="external nofollow"  rel="external nofollow" >testRequestParam</a>
 
</body>

不傳參數(shù)，required()設(shè)置為false，方法有參數(shù)

測(cè)試

@RequestBody

一般用于獲取post請(qǐng)求的方法體，jsp參數(shù)格式為鍵值對(duì)，即 key-value

該注解不適應(yīng)于get請(qǐng)求，一般用于post請(qǐng)求，例如表單提交

如果要用于get請(qǐng)求，則需

@RequestBody(required = false)

否則報(bào)錯(cuò)，此時(shí)方法參數(shù)為null

@RequestMapping(path = "testRequestBody")
    public String testRequestBody(@RequestBody(required = false) String body){
        System.out.println("執(zhí)行了..........");
        System.out.println(body);
        return "success";
    }

<body>
    <%--<a href="anno/testRequestParam" rel="external nofollow"  rel="external nofollow" >testRequestParam</a>--%>
 
    <form action="anno/testRequestBody" method="post">
        用戶名：<input type="text" name="username"/><br>
        密碼：<input type="text" name="password"/><br>
        <input type="submit" value="提交"/><br>
    </form>
</body>

測(cè)試

@PathVariable

URL的占位符，restful風(fēng)格，傳參格式 url地址后/10

restful請(qǐng)求方式： get,post,put 配合注解@RequestMapping設(shè)置請(qǐng)求方式

@RequestMapping(path = "testPathVariable/{sid}",method = RequestMethod.GET)

@RequestMapping(path = "testPathVariable/{sid}",method = RequestMethod.GET)
    /*
    * {sid}表示URL的占位符
    * boolean required() default true;默認(rèn)參數(shù)必須傳
    * */
    public String testPathVariable(@PathVariable("sid") String id){
        System.out.println("執(zhí)行了..........");
        System.out.println(id);
        return "success";
    }

 <a href="anno/testPathVariable/10" rel="external nofollow" >testPathVariable</a>

可以下載postman客戶端，模擬發(fā)送不同的請(qǐng)求方式

測(cè)試：

@RequestHeader

獲取請(qǐng)求頭的某些屬性值如瀏覽器類型、版本等不常用

@RequestMapping(path = "testRequestHeader",method = RequestMethod.GET)
    /*獲取請(qǐng)求頭的某些屬性值 如瀏覽器類型、版本等*/
    public String testRequestHeader(@RequestHeader(value = "Accept") String head){
        System.out.println("執(zhí)行了..........");
        System.out.println(head);
        return "success";
    }

<a href="anno/testRequestHeader" rel="external nofollow" >testRequestHeader</a>

@CookieValue

獲取JSESSIONID的值

@RequestMapping(path = "testCookieValue",method = RequestMethod.GET)
    public String testCookieValue(@CookieValue(value = "JSESSIONID") String JSESSIONID){
        System.out.println("執(zhí)行了..........");
        System.out.println(JSESSIONID);
        return "success";
    }

  <a href="anno/testCookieValue" rel="external nofollow" >testCookieValue</a><br>

@ModelAttribute

用于封裝的數(shù)據(jù)不全補(bǔ)全數(shù)據(jù)，或者檢查封裝數(shù)據(jù)等場(chǎng)景

可作用于方法和參數(shù)

修飾方法，方法入?yún)⑿韬涂刂破鞣椒ㄍ瑓㈩愋停摲椒▋?yōu)先于控制器之前執(zhí)行，且分類有返回值和無(wú)返回值

有返回值，則該方法的返回值和控制器的入?yún)⑾嗤嗤?/li>
無(wú)返回值，則該方法的參數(shù)除了和控制器的入?yún)⑾嗤?，還需加一個(gè)map類型參數(shù)map<string,objct>

例子：

注解修飾的方法有返回值寫(xiě)法

 @RequestMapping(path = "testModelAttribute")
    public String testModelAttribute(User user){
        System.out.println("執(zhí)行了..........");
        System.out.println(user);
        return "success";
    }
 
    @ModelAttribute
    //修飾方法，該方法優(yōu)先于控制器之前執(zhí)行
    public User showUser(User user){
        /*模擬jsp傳的user封裝數(shù)據(jù)不全，
        通過(guò)名字查詢數(shù)據(jù)庫(kù)對(duì)應(yīng)的信息
        返回全的user對(duì)象*/
        user.setBirthday(new Date());
        return user;
    }

<form action="anno/testModelAttribute" method="post">
        用戶名：<input type="text" name="uname"/><br>
        年齡：<input type="text" name="age"/><br>
        <input type="submit" value="提交"/><br>
    </form>

注解修飾的方法無(wú)返回值寫(xiě)法

@RequestMapping(path = "testModelAttribute")
    public String testModelAttribute(@ModelAttribute("key") User user){
        System.out.println("執(zhí)行了..........");
        System.out.println(user);
        return "success";
    }
 
    @ModelAttribute
    //修飾方法，該方法優(yōu)先于控制器之前執(zhí)行
    public void showUser(User user, Map<String,User> userMap){
        /*模擬jsp傳的user封裝數(shù)據(jù)不全，
        通過(guò)名字查詢數(shù)據(jù)庫(kù)對(duì)應(yīng)的信息
        返回全的user對(duì)象*/
        user.setBirthday(new Date());
        userMap.put("key",user);
    }

測(cè)試

@SessionAttributes

注解只能作用于類，用于存取數(shù)據(jù)到session域?qū)ο笾?，?shí)現(xiàn)方法數(shù)據(jù)共享

實(shí)現(xiàn)方式:從request域?qū)ο笾袕?fù)制數(shù)據(jù)到session域中

/**
 * @Date 2019/9/12 2:05
 * by mocar
 */
@Controller
@RequestMapping(path = "/anno")
@SessionAttributes(names = {"msg"})//從request域?qū)ο笾袕?fù)制到session域?qū)ο?
public class annoController {
 
    
    @RequestMapping("/setRequest")//存入
    public String setRequest(ModelMap modelMap){
        System.out.println("setRequest......");
        modelMap.addAttribute("msg","test");//往Request域?qū)ο蟠嬷?
        return "success";
    }
 
    @RequestMapping("/getSession")//獲取
    public String getSession(ModelMap modelMap){
        System.out.println("getSession.......");
        Object msg = modelMap.get("msg");
        System.out.println(msg.toString());
        return "success";
    }
 
    @RequestMapping("/delSession")//刪除
    public String delSession(SessionStatus sessionStatus,ModelMap modelMap){
        System.out.println("delSession.......");
        sessionStatus.setComplete();
        Object msg = modelMap.get("msg");
        System.out.println(msg.toString());
        return "success";
    }
 
}

jsp：

     <br>
    <a href="anno/setRequest" rel="external nofollow" >setRequest</a><br>
    <a href="anno/getSession" rel="external nofollow" >getSession</a><br>
    <a href="anno/delSession" rel="external nofollow" >delSession</a><br>

success.jsp 設(shè)置不忽略EL表達(dá)式，顯示session域數(shù)據(jù)

<%--
  Created by IntelliJ IDEA.
  User: Mocar
  Date: 2019/9/11
  Time: 4:34
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>快速入門(mén)</title>
</head>
<body>
    <h3>success</h3>
 
    ${sessionScope}
 
</body>
</html>

setsession