SpringBoot 3.x Web开发基础
🌐 SpringBoot Web开发概述
SpringBoot提供了强大的Web开发支持，基于Spring MVC框架，可以快速构建RESTful API和传统的Web应用。
核心组件
- DispatcherServlet: 前端控制器，处理所有HTTP请求
- Controller: 控制器，处理具体的业务逻辑
- ViewResolver: 视图解析器，解析视图名称
- HandlerMapping: 处理器映射，将请求映射到处理器
🚀 快速开始
1. 添加Web依赖
xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>这个starter包含了：
- Spring MVC
- 嵌入式Tomcat服务器
- Jackson JSON处理
- 数据验证支持
2. 创建第一个Controller
java
package com.example.demo.controller;
import org.springframework.web.bind.annotation.*;
import java.util.HashMap;
import java.util.Map;
@RestController
@RequestMapping("/api/hello")
public class HelloController {
@GetMapping
public String hello() {
return "Hello, SpringBoot 3.x Web!";
}
@GetMapping("/{name}")
public Map<String, String> helloWithName(@PathVariable String name) {
Map<String, String> response = new HashMap<>();
response.put("message", "Hello, " + name + "!");
response.put("timestamp", java.time.LocalDateTime.now().toString());
return response;
}
@PostMapping
public Map<String, Object> createGreeting(@RequestBody Map<String, String> request) {
String name = request.getOrDefault("name", "World");
Map<String, Object> response = new HashMap<>();
response.put("greeting", "Hello, " + name + "!");
response.put("status", "created");
response.put("id", System.currentTimeMillis());
return response;
}
}🎯 请求映射详解
1. HTTP方法映射
java
@RestController
@RequestMapping("/api/users")
public class UserController {
// GET请求 - 获取所有用户
@GetMapping
public List<User> getAllUsers() {
return userService.findAll();
}
// GET请求 - 根据ID获取用户
@GetMapping("/{id}")
public User getUserById(@PathVariable Long id) {
return userService.findById(id);
}
// POST请求 - 创建用户
@PostMapping
public User createUser(@RequestBody User user) {
return userService.save(user);
}
// PUT请求 - 更新用户
@PutMapping("/{id}")
public User updateUser(@PathVariable Long id, @RequestBody User user) {
return userService.update(id, user);
}
// PATCH请求 - 部分更新用户
@PatchMapping("/{id}")
public User patchUser(@PathVariable Long id, @RequestBody Map<String, Object> updates) {
return userService.patch(id, updates);
}
// DELETE请求 - 删除用户
@DeleteMapping("/{id}")
public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
userService.delete(id);
return ResponseEntity.noContent().build();
}
}2. 请求参数处理
java
@RestController
@RequestMapping("/api/search")
public class SearchController {
// 查询参数
@GetMapping("/users")
public List<User> searchUsers(
@RequestParam(required = false) String name,
@RequestParam(defaultValue = "0") int page,
@RequestParam(defaultValue = "10") int size,
@RequestParam(defaultValue = "id") String sortBy) {
return userService.search(name, page, size, sortBy);
}
// 多个查询参数
@GetMapping("/products")
public List<Product> searchProducts(
@RequestParam Map<String, String> params) {
return productService.search(params);
}
// 路径变量
@GetMapping("/category/{categoryId}/products/{productId}")
public Product getProduct(
@PathVariable Long categoryId,
@PathVariable Long productId) {
return productService.findByCategoryAndId(categoryId, productId);
}
// 请求头
@GetMapping("/profile")
public UserProfile getUserProfile(
@RequestHeader("Authorization") String token,
@RequestHeader(value = "User-Agent", required = false) String userAgent) {
return userService.getProfile(token, userAgent);
}
}3. 请求体处理
java
@RestController
@RequestMapping("/api/orders")
public class OrderController {
// JSON请求体
@PostMapping
public Order createOrder(@RequestBody @Valid OrderRequest request) {
return orderService.create(request);
}
// 表单数据
@PostMapping("/form")
public Order createOrderFromForm(
@RequestParam String customerName,
@RequestParam String email,
@RequestParam List<Long> productIds) {
OrderRequest request = new OrderRequest(customerName, email, productIds);
return orderService.create(request);
}
// 文件上传
@PostMapping("/upload")
public ResponseEntity<String> uploadFile(
@RequestParam("file") MultipartFile file,
@RequestParam("description") String description) {
if (file.isEmpty()) {
return ResponseEntity.badRequest().body("文件不能为空");
}
try {
String fileName = fileService.store(file, description);
return ResponseEntity.ok("文件上传成功: " + fileName);
} catch (Exception e) {
return ResponseEntity.status(500).body("文件上传失败: " + e.getMessage());
}
}
}📝 数据验证
1. 使用Bean Validation
java
package com.example.demo.dto;
import jakarta.validation.constraints.*;
import java.time.LocalDate;
public class UserRequest {
@NotBlank(message = "用户名不能为空")
@Size(min = 2, max = 50, message = "用户名长度必须在2-50个字符之间")
private String username;
@NotBlank(message = "邮箱不能为空")
@Email(message = "邮箱格式不正确")
private String email;
@NotNull(message = "年龄不能为空")
@Min(value = 18, message = "年龄不能小于18岁")
@Max(value = 100, message = "年龄不能大于100岁")
private Integer age;
@Pattern(regexp = "^1[3-9]\\d{9}$", message = "手机号格式不正确")
private String phone;
@Past(message = "生日必须是过去的日期")
private LocalDate birthday;
// 构造函数、getter和setter方法
public UserRequest() {}
public String getUsername() { return username; }
public void setUsername(String username) { this.username = username; }
public String getEmail() { return email; }
public void setEmail(String email) { this.email = email; }
public Integer getAge() { return age; }
public void setAge(Integer age) { this.age = age; }
public String getPhone() { return phone; }
public void setPhone(String phone) { this.phone = phone; }
public LocalDate getBirthday() { return birthday; }
public void setBirthday(LocalDate birthday) { this.birthday = birthday; }
}🔗 下一篇
在下一篇文章中，我们将学习RESTful API的设计原则和最佳实践。
本文关键词: Web开发, Spring MVC, Controller, 请求映射, 数据验证, RESTful