通過ServletAPI獲取

test.html

<a th:href="@{/testServletAPI(username='admin',password=123456)}">連結</a>

控制器

    @RequestMapping("/testServletAPI")

    public String testServletAPI(HttpServletRequest request){

        String username = request.getParameter("username");

        String password = request.getParameter("password");

        System.out.println("username:"+username+" password:"+password);

        return "welcome";

    }

	//輸出：username:admin password:123456

通過控制器方法的形參獲取請求引數

在控制器方法的形參位置，設定和請求引數同名的形參，當瀏覽器傳送請求，匹配到請求對映時，在

DispatcherServlet中就會將請求引數賦值給相應的形參

test.html

<form th:action="@{/testServletAPI}" method="post">

    使用者名稱<input type="text" name="username"/> <br>

    密碼<input type="password" name="password"> <br>

    愛好

    <input type="checkbox" name="hobby" value="a">a

    <input type="checkbox" name="hobby" value="b">b

    <input type="checkbox" name="hobby" value="c">c

    <br>

    <input type="submit" value="提交">

</form>

控制器

    @RequestMapping("/testServletAPI")

    public String testServletAPI(String username, String password,String hobby){

        System.out.println("username:"+username+" password:"+password+" hobby:"+hobby);

        return "welcome";

    }

	//輸出：username:admin password:123456 hobby:a,b,c

若使用字串型別的形參，此引數的值為每個資料中間使用逗號拼接的結果

    @RequestMapping("/testServletAPI")

    public String testServletAPI(String username, String password,String[] hobby){

        System.out.println("username:"+username+" password:"+password+" hobby:"+ Arrays.toString(hobby));

        return "welcome";

    }

	//輸出：username:admin password:123456 hobby:[a, b, c]

若使用字串陣列型別的形參，此引數的陣列中包含了每一個數據

@RequestParam

將請求引數和控制器方法的形參建立對映關係

value：指定為形參賦值的請求引數的引數名

required：設定是否必須傳輸此請求引數，預設值為true。若設定為true時，則當前請求必須傳輸value所指定的請求引數，若沒有傳輸該請求引數，且沒有設定defaultValue屬性，則頁面報錯400：Required String parameter 'xxx' is not present；若設定為false，則當前請求不是必須傳輸value所指定的請求引數，若沒有傳輸，則註解所標識的形參的值為null

defaultValue：不管required屬性值為true或false，當value所指定的請求引數沒有傳輸或傳輸的值

為""時，則使用預設值為形參賦值

    @RequestMapping("/testServletAPI")

    public String testServletAPI(

            @RequestParam(value = "user_name", required = true, defaultValue = "admin") String username,

            String password,String[] hobby){

        System.out.println("username:"+username+" password:"+password+" hobby:"+ Arrays.toString(hobby));

        return "welcome";

    }

test.html

<form th:action="@{/testServletAPI}" method="post">

    使用者名稱<input type="text" name="user_name"/> <br>

    密碼<input type="password" name="password"> <br>

    愛好

    <input type="checkbox" name="hobby" value="a">a

    <input type="checkbox" name="hobby" value="b">b

    <input type="checkbox" name="hobby" value="c">c

    <br>

    <input type="submit" value="提交">

</form>

輸出：username:admin password:123 hobby:[a, b, c]

@RequestHeader

將請求頭資訊和控制器方法的形參建立對映關係

共有三個屬性：value、required、defaultValue，用法同@RequestParam

    @RequestMapping("/testServletAPI")

    public String testServletAPI(

            @RequestParam(value = "user_name", required = true, defaultValue = "admin") String username,

            String password,String[] hobby,

            @RequestHeader(value = "Host") String host){

        System.out.println("username:"+username+" password:"+password+" hobby:"+ Arrays.toString(hobby));

        System.out.println(host);

        return "welcome";

    }

	//輸出：username:admin password:123 hobby:[a, b, c]

    //         localhost:8080

@CookieValue

將cookie資料和控制器方法的形參建立對映關係

共有三個屬性：value、required、defaultValue，用法同@RequestParam

    @RequestMapping("/testServletAPI")

    public String testServletAPI(

            @RequestParam(value = "user_name", required = true, defaultValue = "admin") String username,

            String password,String[] hobby,

            @RequestHeader(value = "Host") String host,

            @CookieValue("JSESSIONID") String JSESSIONID){

        System.out.println("username:"+username+" password:"+password+" hobby:"+ Arrays.toString(hobby));

        System.out.println(host);

        System.out.println(JSESSIONID);

        return "welcome";

    }

	//輸出：username:admin password:123 hobby:[a, b, c]

	//     localhost:8080

	//     B41B43E2F9C58645137BA27918340B58

通過POJO獲取請求引數

可以在控制器方法的形參位置設定一個實體類型別的形參，此時若瀏覽器傳輸的請求引數的引數名和實體類中的屬性名一致，那麼請求引數就會為此屬性賦值

test.html

<form th:action="@{/testBean}" method="get">

    使用者名稱：<input type="text" name="username"><br>

    密碼：<input type="password" name="password"><br>

    性別：<input type="radio" name="sex" value="男">男<input type="radio" name="sex" value="女">女<br>

    年齡：<input type="text" name="age"><br>

    郵箱：<input type="text" name="email"><br>

    <input type="submit" value="使用實體類接受請求引數">

</form>

按照test.html表單的欄位編寫User.java的bean類，包括有參和無參構造，get和set方法

控制器

    @RequestMapping("/testBean")

    public String testBean(User user){

        System.out.println(user);

        return "welcome";

    }

輸出：User{id=null, username='admin', password='333', age=19, sex='男', email='[email protected]'}

解決獲取請求引數的亂碼問題

解決獲取請求引數的亂碼問題，可以使用SpringMVC提供的編碼過濾器CharacterEncodingFilter，但是必須在web.xml中進行註冊

<filter>

    <filter-name>CharacterEncodingFilter</filter-name>

    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

    <init-param>

        <param-name>encoding</param-name>

        <param-value>UTF-8</param-value>

    </init-param>

    <init-param>

        <param-name>forceResponseEncoding</param-name>

        <param-value>true</param-value>

    </init-param>

</filter>

<filter-mapping>

    <filter-name>CharacterEncodingFilter</filter-name>

    <url-pattern>/*</url-pattern>

</filter-mapping>