Spring Web MVC从入门实例到实战教程

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<dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-web</artifactId>

</dependency>

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@RestController

@RequestMapping("/user") // 类级路由前缀

public class UserController {

    // 方法级路由，完整访问路径：/user/sayHi

    @RequestMapping("/sayHi")

    public String sayHi() {

        return "hello, Spring MVC";

    }

}

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@RequestMapping("/r6")

// 此处@RequestParam("sa")注解的作用是参数重命名，

public String r6(@RequestParam(value = "sa", required = false) String resouce){

    return "接收到 resouce = " + resouce;

}

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@RequestMapping("/r11/{articleId}/{type}")

public String r11(@PathVariable("articleId") Integer id, @PathVariable String type){

    return "接收到的参数 articleId = " + id + ", type = " + type;

}

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// 返回视图（需配合模板引擎）

@Controller

public class IndexController {

    @RequestMapping("/index")

    public String index() {

        return "/index.html";

    }

}

// 返回数据

@RestController

public class DataController {

    @RequestMapping("/data")

    public String getData() {

        return "这是返回的数据内容";

    }

}

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@RequestMapping("/r1")

public String r1(String name){

    return "接收到参数 name = " + name;

}

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@RequestMapping("/r4")

    public String r4(String name, String password, Integer age){

        // 此处字符串拼接不考虑性能

        return "接收到参数 name = " + name + ", password = " + password + ", age = " + age;

    }

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// 实体类

public class Person {

    private  String name;

    private String password;

    private int age;

    public String getName() {

        return name;

    }

    public String getPassword() {

        return password;

    }

    public int getAge() {

        return age;

    }

    public void setName(String name) {

        this.name = name;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public void setAge(int age) {

        this.age = age;

    }

    @Override

    public String toString() {

        return "Person{" +

                "name='" + name + '\'' +

                ", password='" + password + '\'' +

                ", age=" + age +

                '}';

    }

}

// 接口方法

@RequestMapping("/r5")

public String r4(Person person){

    return "接收到参数 person = " + person;

}

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@RequestMapping("/r6")

// 此处@RequestParam()注解的作用是参数重命名

public String r6(@RequestParam("sa") String resouce){

    return "接收到 resouce = " + resouce;

}

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@RequestMapping("/r7")

public String r7(String[] names){

    return "接收到参数 names = " + Arrays.toString(names);

}

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@RequestMapping("/r8")

// @RequestParam 在这里的作用是将请求中的参数绑定到方法的 List<String> names 参数上

public String r8(@RequestParam List<String> names){

    return "接收到的参数 names = " + names;

}

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{

  "userId": 1001,

  "userName": "zhangsan",

  "age": 25,

  "isStudent": false,

  "hobbies": ["reading", "coding"]

}

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[

  {"bookId": 1, "bookName": "Spring MVC实战"},

  {"bookId": 2, "bookName": "Java核心技术"},

  3.14,

  "JSON教程"

]

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package cn.overthinker.springboot;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import org.junit.jupiter.api.Test;

public class JSONTests {

    private  static ObjectMapper objectMapper = new ObjectMapper();

    public static void main(String[] args) throws JsonProcessingException {

        Person person = new Person();

        person.setName("zhangsan");

        person.setAge(18);

        person.setPassword("123456");

        // 对象转json字符串

        String s = objectMapper.writeValueAsString(person);

        System.out.println(s);

        //json字符串转对象

        String json = "{\"name\":\"zhangsan\",\"age\":18,\"password\":\"123456\"}";

        Person person1 = objectMapper.readValue(json, Person.class);

        System.out.println(person1);

    }

}

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List<Person> personList = objectMapper.readValue(

    "[{\"id\":1,\"name\":\"zhangsan\"},{\"id\":2,\"name\":\"lisi\"}]",

    new TypeReference<List<Person>>() {}

);

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@RequestMapping("/r9")

public String r9(@RequestBody Person person){

    return "接收到的参数 person = " + person;

}

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@RequestMapping("/r12")

    // 处理文件上传的请求方法，MultipartFile是Spring提供的文件上传封装类

    // throws IOException：声明可能抛出的IO异常（文件读写时可能发生）

    public String r12(MultipartFile file) throws IOException{

        // 1. 获取表单中文件参数的名称（即前端<input type="file" name="file">中的name值）

        // 注意：此名称是前端表单控件的name属性值，而非实际文件名

        System.out.println("表单文件参数名：" + file.getName());

        // 2. 获取上传文件的原始名称（包含文件名和扩展名，如"test.jpg"）

        // 该名称来自客户端本地文件的名称，可能包含路径（不同浏览器处理不同，需注意）

        System.out.println("文件原始名称：" + file.getOriginalFilename());

        // 3. 获取文件的MIME类型（如图片为"image/jpeg"，文本为"text/plain"）

        // 用于判断文件类型，可用于限制上传文件格式（如只允许图片上传）

        System.out.println("文件MIME类型：" + file.getContentType());

        // 4. 定义文件保存路径和文件名

        // 这里将文件保存到本地"D:/temp/"目录，文件名使用原始文件名

        // 注意：需确保"D:/temp/"目录已存在，否则会抛出文件找不到异常

        File destFile = new File("D:/temp/" + file.getOriginalFilename());

        // 5. 将上传的文件内容转移到目标文件中

        // transferTo()是Spring提供的便捷方法，内部处理了文件流的读写和关闭

        // 替代了传统的InputStream/OutputStream手动读写逻辑，更安全高效

        file.transferTo(destFile);

        // 6. 返回上传成功的提示信息

        return "接受到文件，已保存至D:/temp目录";

    }

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import jakarta.servlet.http.Cookie;

import jakarta.servlet.http.HttpServletRequest;

import jakarta.servlet.http.HttpServletResponse;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

@RequestMapping("/request2")

public class RequestController2 {

    /***

     * 读取cookie

     */

    @RequestMapping("/getCookie")

    public String getCookie(HttpServletRequest request, HttpServletResponse response) {

        Cookie[] cookies = request.getCookies();

        if(cookies != null){

            for(Cookie cookie : cookies){

                System.out.println(cookie.getName() + ":" + cookie.getValue());

            }

        }

        return "获取Cookie成功";

    }

}

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@RequestMapping("/getCookie2")

// 要求客户端必须返回含class名称的cookie

public String getCookie2(@CookieValue("class") String className) {

   return "获取Cookie成功 className:" + className;

}

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@RequestMapping("/setSession")

    public String setSession(HttpServletRequest request){

        HttpSession session = request.getSession();

        session.setAttribute("name", "zhangsan");

        session.setAttribute("age", 20);

        return "设置Session成功";

    }

    @RequestMapping("/getSession")

    public String getSession(HttpServletRequest request){

        HttpSession session = request.getSession();

        String name = (String) session.getAttribute("name");

        Integer age = (Integer) session.getAttribute("age");

        return "从session中获取数据， name:" + name + ", age:" + age;

    }

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// 通过HttpSession直接获取session

@RequestMapping("/getSession")

public String getSession(HttpSession session){

    // 获取用户信息

    String name = (String) session.getAttribute("name");

    Integer age = (Integer) session.getAttribute("age");

    return "从session中获取数据， name:" + name + ", age:" + age;

}

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@RequestMapping("/getSession3")

public String getSession3(@SessionAttribute("name") String name){

    // 获取用户信息

    return "从session中获取数据， name:" + name;

}

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/***

     * 读取session

     * @param request

     * @return

     */

    @RequestMapping("/setSession")

    public String setSession(HttpServletRequest request, String name){

        HttpSession session = request.getSession();

        session.setAttribute("name", name);

        session.setAttribute("age", 20);

        return "设置Session成功";

    }

        // 通过HttpSession直接获取session

    @RequestMapping("/getSession2")

    public String getSession(HttpSession session){

        // 获取用户信息

        String name = (String) session.getAttribute("name");

        Integer age = (Integer) session.getAttribute("age");

        return "从session中获取数据， name:" + name + ", age:" + age;

    }

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@RequestMapping("/getHeader")

public String getHeader(HttpServletRequest request){

    String userAgent = request.getHeader("User-Agent");

    return "从Header获取数据， userAgent" + userAgent;

}

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//使用注解

  @RequestMapping("/getHeader2")

  public String getHeader(@RequestHeader("User-Agent") String userAgent){

      return "从Header获取数据， userAgent" + userAgent;

  }

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@Controller

public class IndexController {

    @RequestMapping("/index")

    public Object index() {

        return "/index.html";

    }

}

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@RequestMapping("/returnJson")

@ResponseBody

public HashMap<String, String> returnJson() {

    HashMap<String, String> map = new HashMap<>();

    map.put("Java", "Java Value");

    map.put("MySQL", "MySQL Value");

    map.put("Redis", "Redis Value");

    return map;

}

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{"Java":"Java Value","MySQL":"MySQL Value","Redis":"Redis Value"}

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@ResponseBody

@RequestMapping("/returnJSON")

public Person returnJSON(){

    // 实例化数据模型对象

    Person person = new Person();

    // 设置对象属性

    person.setName("zhangsan");

    person.setAge(18);

    person.setPassword("123456");

    // 返回对象，由 @ResponseBody 自动转换为 JSON

    return person;

}

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{"name":"zhangsan","password":"123456","age":18}

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@RequestMapping("/setStatus")

@ResponseBody

public String setStatus(HttpServletResponse response) {

    response.setStatus(401); // 未授权状态码

    return "设置状态码成功";

}

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@RequestMapping("/setHeader")

@ResponseBody

public String setHeader(HttpServletResponse response) {

    response.setHeader("MyHeader", "MyHeaderValue");

    return "设置Header成功";

}

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@RestController

@RequestMapping("/calc")

public class CalcController {

    @RequestMapping("/sum")

    public String sum(Integer num1, Integer num2) {

        Integer sum = num1 + num2;

        return "<h1>计算机计算结果: " + sum + "</h1>";

    }

}

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<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>加法计算器</title>

</head>

<body>

    <form action="calc/sum" method="post">

        <h1>计算器</h1>

        数字1:<input name="num1" type="text">

        数字2:<input name="num2" type="text">

        <input type="submit" value="点击相加">

    </form>

</body>

</html>

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@RestController

@RequestMapping("/user")

public class LoginController {

    // 登录校验

    @RequestMapping("/login")

    public boolean login(String userName, String password, HttpSession session) {

        if (!StringUtils.hasLength(userName) || !StringUtils.hasLength(password)) {

            return false;

        }

        // 模拟数据库校验

        if ("zhangsan".equals(userName) && "123456".equals(password)) {

            session.setAttribute("userName", userName);

            return true;

        }

        return false;

    }

    // 获取当前登录用户

    @RequestMapping("/getLoginUser")

    public String getLoginUser(HttpSession session) {

        String userName = (String) session.getAttribute("userName");

        if (StringUtils.hasLength(userName)) {

            return userName;

        }

        return "";

    }

}

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@RestController

@RequestMapping("/book")

public class BookController {

    @RequestMapping("/getList")

    public List<BookInfo> getList() {

        BookService bookService = new BookService();

        return bookService.getBookList();

    }

}

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function getBookList() {

    $.ajax({

        type: "get",

        url: "/book/getList",

        success: function (result) {

            if (result != null) {

                var finalHtml = "";

                for (var book of result) {

                    finalHtml += '<tr>';

                    finalHtml += '<td><input type="checkbox" name="selectBook" value="' + book.id + '"></td>';

                    finalHtml += '<td>' + book.id + '</td>';

                    finalHtml += '<td>' + book.bookName + '</td>';

                    finalHtml += '<td>' + book.author + '</td>';

                    finalHtml += '<td>' + book.count + '</td>';

                    finalHtml += '<td>' + book.price + '</td>';

                    finalHtml += '<td>' + book.publish + '</td>';

                    finalHtml += '<td>' + book.statusCN + '</td>';

                    finalHtml += '<td><a href="book_update.html?bookId=' + book.id + '" rel="external nofollow" >修改</a> | <a href="javascript:deleteBook(' + book.id + ')" rel="external nofollow" >删除</a></td>';

                    finalHtml += "</tr>";

                }

                $("tbody").html(finalHtml);

            }

        }

    });

}

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<dependency>

    <groupId>org.projectlombok</groupId>

    <artifactId>lombok</artifactId>

    <optional>true</optional>

</dependency>

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@Data

@NoArgsConstructor

@AllArgsConstructor

public class Person {

    private int id;

    private String name;

    private String password;

}