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24_02SpringMVC的常用注解

Posted on 2020-01-03 19:30  心默默言  阅读(143)  评论(0)  编辑  收藏  举报

1.RequestParam

1.1使用说明

1.2使用示例

如下参数名称不一致，则获取不到参数。

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<a href="anno/testRequestParam?name=哈哈">RequestParam</a>
</body>
</html>
package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testRequestParam")
    public String testRequestParam(String username){
        System.out.println("执行了...");
        System.out.println(username);
        return "success";
    }

}

 

解决方法：

package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testRequestParam")
    public String testRequestParam(@RequestParam(name = "name") String username){
        System.out.println("执行了...");
        System.out.println(username);
        return "success";
    }

}

2. RequestBody

2.1使用说明

2.2使用示例

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<form action="anno/testRequestBody" method="post">
    用户姓名：<input type="text" name="username" /><br/>
    用户年龄：<input type="text" name="age" /><br/>
    <input type="submit" value="提交" />
</form>
</body>
</html>
package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testRequestBody")
    public String testRequestBody(@RequestBody String body){ //注解描述拿到的是请求体，而不是body属性
        System.out.println("执行了...");
        System.out.println(body);
        return "success";
    }

}

3.PathVaribale

3.1使用说明

3.2使用示例

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<a href="anno/testPathVariable/10">testPathVariable</a>
</body>
</html>
package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testPathVariable/{sid}")
    public String testPathVariable(@PathVariable(name = "sid") String id){ //注解描述拿到的是请求体，而不是body属性
        System.out.println("执行了...");
        System.out.println(id);
        return "success";
    }

}

4.RequestHeader

4.1使用说明

4.2使用示例

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<a href="anno/testRequestHeader">testRequestHeader</a>
</body>
</html>
package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testRequestHeader")
    public String testRequestHeader(@RequestHeader(value = "accept") String header) { //注解描述拿到的是请求体，而不是body属性
        System.out.println("执行了...");
        System.out.println(header);
        return "success";
    }

}

5.CookieValue

5.1使用说明

5.2使用示例

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<a href="anno/testCookieValue">testCookieValue</a>
</body>
</html>
package cn.itcast.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testCookieValue")
    public String testCookieValue(@CookieValue(value="JSESSIONID") String cookieValue) { //注解描述拿到的是请求体，而不是body属性
        System.out.println("执行了...");
        System.out.println(cookieValue);
        return "success";
    }

}

6. ModelAttribute

6.1 使用说明

6.2使用示例

1.方法有返回值

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<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>
</body>
</html>
package cn.itcast.controller;

import cn.itcast.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Date;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testModelAttribute")
    public String testModelAttribute(User user) { //注解描述拿到的是请求体，而不是body属性
        System.out.println("testModelAttribute执行了...");
        System.out.println(user);
        return "success";
    }
}

 

 因为只封装了两个参数，第三个参数为空。

如果，第三个参数我想要用数据库里面已经存在的参数，可以如下操作：

package cn.itcast.controller;

import cn.itcast.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.Date;

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testModelAttribute")
    public String testModelAttribute(User user) { //注解描述拿到的是请求体，而不是body属性
        System.out.println("testModelAttribute执行了...");
        System.out.println(user);
        return "success";
    }
    @ModelAttribute
    public User showUser(String uname){
        System.out.println("showUser执行了...");
        // 通过用户查询数据库（模拟）
        User user = new User();
        user.setUname(uname);
        user.setAge(20);
        user.setDate(new Date());
        return user;
    }
}

2.方法没有返回值

package cn.itcast.controller;

import cn.itcast.domain.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

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

/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
public class AnnoController {
    @RequestMapping("/testModelAttribute")
    public String testModelAttribute(@ModelAttribute("abc") User user) { //注解描述拿到的是请求体，而不是body属性
        System.out.println("testModelAttribute执行了...");
        System.out.println(user);
        return "success";
    }

    @ModelAttribute
    public void showUser(String uname, Map<String,User> map){
        System.out.println("showUser执行了...");
        // 通过用户查询数据库（模拟）
        User user = new User();
        user.setUname(uname);
        user.setAge(20);
        user.setDate(new Date());
        map.put("abc",user);
    }
}

7.SessionAttribute

7.1使用说明

7.2使用示例

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%--常用注解--%>
<a href="anno/testSessionAttributes">testSessionAttributes</a>
<a href="anno/getSessionAttributes">getSessionAttributes</a>
<a href="anno/delSessionAttributes">delSessionAttributes</a>
</body>
</html>
package cn.itcast.controller;

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;


/**
 * 常用的注解
 */
@Controller
@RequestMapping("/anno")
@SessionAttributes(value={"msg"})   // 把msg=美美存入到session域对中
public class AnnoController {
    @RequestMapping(value = "/testSessionAttributes")
    public String testSessionAttributes(Model model) {
        System.out.println("testSessionAttributes...");
        // 底层会存储到request域对象中
        model.addAttribute("msg", "美美");
        return "success";
    }

    @RequestMapping(value = "/getSessionAttributes")
    public String getSessionAttributes(ModelMap modelMap) {
        System.out.println("getSessionAttributes...");
        String msg = (String) modelMap.get("msg");
        System.out.println(msg);
        return "success";
    }

    @RequestMapping(value = "/delSessionAttributes")
    public String delSessionAttributes(SessionStatus status) {
        System.out.println("delSessionAttributes...");
        status.setComplete();
        return "success";
    }
}