如何建设网站赚钱浙江高端建设网站
目录
学习Spring MVC
一、建立连接
@RestController和@RequestMapping
@RequestMapping 使用
访问地址：类路径+方法路径
既支持Get请求又支持Post请求
⭐️指定GET方法类型
🌙指定POST方法类型
二、请求
1️⃣传递单个参数
2️⃣传递多个参数
3️⃣传递对象
4️⃣后端参数重命名（后端参数映射）
非必传参数设置
5️⃣传递数组
6️⃣传递集合
7️⃣传递JSON数据
JSON字符串和Java对象互转
传递JSON对象
传递对象和传递JSON的区别
8️⃣获取URL中参数@PathVariable
参数重命名
9️⃣上传文件@RequestPart
参数重命名
🔟 获取Cookie/Session
📝面经： Cookie 和 Session 的区别
获取Cookie
🍃传统获取Cookie
🍂简洁获取Cookie：@CookieValue
Session存储
获取Session
🍈方式一：
🍒方式二：
🥥方式三： @SessionAttribute
1️⃣1️⃣获取Header
🌭传统获取 header
🍔简洁获取 Header：@RequestHeader
三、响应
返回静态页面：@Controller
前端代码
后端代码
返回数据：@ResponseBody
返回HTML代码片段
返回JSON
设置状态码
设置Header (了解)
设置Content-Type
设置其他Header
Spring Web MVC咱们简称之为: Spring MVC
Spring MVC 是⼀个实现了 MVC 模式的 Web 框架
学习Spring MVC
一、建立连接
将用户（浏览器）和 Java 程序连接起来，也就是访问⼀个地址能够调用到我们的Spring 程序
@RestController和@RequestMapping
@RestController
public class UserController {@RequestMapping("/hello")public String sayHello() {return "Hello Spring";}
}
@RequestMapping 使用
访问地址：类路径+方法路径
@RestController
@RequestMapping("/user")
public class UserController {@RequestMapping("/hello")public String sayHello() {return "Hello Spring";}
}
既支持Get请求又支持Post请求
⭐️指定GET方法类型
@RestController
@RequestMapping("/user")
public class UserController {@RequestMapping(value = "/hello", method = RequestMethod.GET)public String sayHello() {return "Hello Spring";}
}@GetMapping
@RestController
@RequestMapping("/user")
public class UserController {@GetMapping("/hello")public String sayHello() {return "Hello Spring";}
}🌙指定POST方法类型
@RestController
@RequestMapping("/user")
public class UserController {@RequestMapping(value = "/hello", method = RequestMethod.POST)public String sayHello() {return "Hello Spring";}
}@PostMapping
@RestController
@RequestMapping("/user")
public class UserController {@PostMapping("/hello")public String sayHello() {return "Hello Spring";}
}二、请求
用户请求的时候会带⼀些参数，在程序中要想办法获取到参数，所以请求这块主要是获取参数的功能
传递的普通参数，默认类型为String，后端接收时，会根据后端定义的类型来转换
1️⃣传递单个参数
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p1")public String p1(String name) {return "接收到参数 name:" + name;}
}
2️⃣传递多个参数
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p2")public String p2(String name, Integer age) {return "接收到参数,age:" + age + ", name:" + name;}
}
3️⃣传递对象
public class User {private String name;private Integer age;private Integer gender;public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Integer getGender() {return gender;}public void setGender(Integer gender) {this.gender = gender;}@Overridepublic String toString() {return "User{" +"name='" + name + '\'' +", age=" + age +", gender=" + gender +'}';}
}@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p3")public String p3(User user) {return "user:" + user;}
}
4️⃣后端参数重命名（后端参数映射）
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p4")public String p4(@RequestParam("userName") String name, Integer age) {return "接收到参数,age:" + age + ", name:" + name;}
}
使用@RequestParam进行参数重命名时，请求参数只能和@RequestParam声明的名称一
致，才能进行参数绑定和赋值.
使用@RequestParam进行参数重命名时，参数就变成了必传参数.
非必传参数设置
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p4")public String p4(@RequestParam(value = "userName", required = false) String name, Integer age) {return "接收到参数,age:" + age + ", name:" + name;}
}
5️⃣传递数组
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p5")public String p5(String[] arr) {return "arr:" + List.of(arr);}
}
6️⃣传递集合
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p6")public String p6(@RequestParam List<String> list) {return "list:" + list;}
}
7️⃣传递JSON数据
JSON字符串和Java对象互转
package com.example.demo;import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;public class JsonTest {public static void main(String[] args) throws JsonProcessingException {ObjectMapper objectMapper = new ObjectMapper();User user = new User();user.setName("lisi");user.setAge(18);user.setGender(1);// 对象转jsonString s = objectMapper.writeValueAsString(user);System.out.println(s);//json转对象User user1 = objectMapper.readValue(s, User.class);System.out.println(user1);}
}
传递JSON对象
@RequestBody
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p7")public String p7(@RequestBody User user) {//从请求正文中return "User:" + user;}
}
传递对象和传递JSON的区别
8️⃣获取URL中参数@PathVariable
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/article/{articleId}")public String p8(@PathVariable("articleId") String articleId) {//从请求正文中return "articleId:" + articleId;}
}
参数重命名
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/article/{articleId}/{name}")public String p8(@PathVariable("articleId") String id, @PathVariable String name) {//从请求正文中return "articleId:" + id + ",name:" + name;}
}
如果方法参数名称和需要绑定的URL中的变量名称一致时，可以简写， 不用给@PathVariable的属性赋值
如果方法参数名称和需要绑定的URL中的变量名称不一致时， 需要给@PathVariable的属性value赋值
9️⃣上传文件@RequestPart
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p9")public String p9(MultipartFile file) {System.out.println(file.getOriginalFilename());return "文件名称：" + file.getOriginalFilename();}
}
参数重命名
@RequestMapping("/param")
@RestController
public class ParamController {@RequestMapping("/p9")public String p9(@RequestPart("fileName") MultipartFile file) {System.out.println(file.getOriginalFilename());return "文件名称：" + file.getOriginalFilename();}
}
🔟 获取Cookie/Session
📝面经： Cookie 和 Session 的区别
●Cookie是客户端保存用户信息的一种机制.Session是服务器端保存用户信息的一种机制.
●Cookie和Session之间主要是通过Sessionld关联起来的，Sessionld是Cookie和Session之间的桥梁
●Cookie和Session经常会在一起配合使用.但是不是必须配合.
o 完全可以用Cookie来保存一些数据在客户端.这些数据不一定是用户身份信息，也不一定是Sessionld
o Session中的sessionld也不需要非得通过Cookie/Set-Cookie传递，比如通过URL传递.
获取Cookie
🍃传统获取Cookie
@RestController
@RequestMapping("/header")
public class HeaderController {@RequestMapping("/getCookie")public String getCookie(HttpServletRequest request) {Cookie[] cookies = request.getCookies();if (cookies != null) {for (Cookie cookie : cookies) {System.out.println(cookie.getName() + ":" + cookie.getValue());}}return "获取cookie成功";}
}
🍂简洁获取Cookie：@CookieValue
@RestController
@RequestMapping("/header")
public class HeaderController {@RequestMapping("/getCookie")public String getCookie2(@CookieValue("baidu") String baidu) {return "从Cookie中获取信息,baidu:" + baidu;}
}
Session存储
@RestController
@RequestMapping("/header")
public class HeaderController {@RequestMapping("/setSession")public String setSession(HttpServletRequest request) {HttpSession session = request.getSession();session.setAttribute("userName", "zhangsan");session.setAttribute("age", "15");return "设置session成功";}
}获取Session
🍈方式一：
@RequestMapping("/getSession")public String getSession(HttpServletRequest request) {HttpSession session = request.getSession();if (session != null) {String userName = (String) session.getAttribute("userName");System.out.println(session.getAttribute("age"));return "从session中获取信息，userName:" + userName;}return null;}🍒方式二：
@RequestMapping("/getSession")public String getSession(HttpSession session) {if (session != null) {String userName = (String) session.getAttribute("userName");System.out.println(session.getAttribute("age"));return "从session中获取信息，userName:" + userName;}return null;}🥥方式三： @SessionAttribute
@RequestMapping("/getSession")public String getSession(@SessionAttribute("userName") String userName) {return "从session中获取信息，userName:" + userName;}1️⃣1️⃣获取Header
🌭传统获取 header
@RestController
@RequestMapping("/header")
public class HeaderController {@RequestMapping("/getHeader")public String getHeader(HttpServletRequest request) {String uesrAgent = request.getHeader("User-Agent");return "uesrAgent:" + uesrAgent;}
}
🍔简洁获取 Header：@RequestHeader
@RestController
@RequestMapping("/header")
public class HeaderController {@RequestMapping("/getHeader")public String getHeader(@RequestHeader("User-Agent") String uesrAgent) {return "uesrAgent:" + uesrAgent;}
}三、响应
返回静态页面：@Controller
前端代码
后端代码
@RequestMapping("/response")
@Controller
public class ResponseController {@RequestMapping("/returnHtmlPage")public String returnHtmlPage() {return "/hello.html";}
}
返回数据：@ResponseBody
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/returnHtmlPage")public String returnHtmlPage() {return "/hello.html";}
}
返回HTML代码片段
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/returnHtml")public String returnHtml() {return "<h1>returnHtml<h1>";}
}
返回JSON
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/returnJson")public User returnJson() {User user = new User();user.setName("zhangsan");user.setAge(18);return user;}
}
设置状态码
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/setStatus")public User setStatus(HttpServletResponse response) {User user = new User();user.setName("zhangsan");user.setAge(18);response.setStatus(500);return user;}
}
设置Header (了解)
设置Content-Type
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/setHeader")public String setHeader() {return "{\"success\":true}";}
}
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping(value = "/setHeader",produces = "application/json")public String setHeader() {return "{\"success\":true}";}
}
设置其他Header
@RequestMapping("/response")
@Controller
@ResponseBody
public class ResponseController {@RequestMapping("/setHeader")public String setHeader(HttpServletResponse response) {response.setHeader("myKey", "myValue");return "success";}
}