Spring 01
今天是2025/0420 19:44 day 21
总路线请移步主页Java大纲相关文章
今天进行Spring 1,2,3 个模块的归纳
最近在忙毕设，更新有点慢，见谅
首先是Spring 的相关内容概括的思维导图
一、核心概念详解
1. IoC容器
1.1 工作原理
// 典型使用示例
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
UserService userService = context.getBean(UserService.class);
1.2 依赖注入方式对比
| 方式 | 优点 | 缺点 |
|---|---|---|
| 构造器注入 | 不可变对象，强依赖 | 参数多时代码臃肿 |
| Setter注入 | 灵活性高 | 对象可能处于部分初始化状态 |
| 字段注入 | 代码简洁 | 难以测试，隐藏依赖关系 |
1.3 注解驱动开发
@Configuration
public class AppConfig {
@Bean
public DataSource dataSource() {
return new DriverManagerDataSource(...);
}
}
2. AOP编程
2.1 核心概念图解
[业务组件] --交叉关注点--> [日志/事务/安全] \ / \ / [AOP代理层]
2.2 通知类型示例
@Aspect
public class LogAspect {
@Before("execution(* com.example.service.*.*(..))")
public void logBefore(JoinPoint jp) {
System.out.println("方法调用前: " + jp.getSignature());
}
@Around("@annotation(com.example.Monitor)")
public Object monitorPerformance(ProceedingJoinPoint pjp) throws Throwable {
long start = System.currentTimeMillis();
Object result = pjp.proceed();
System.out.println("方法执行耗时: " + (System.currentTimeMillis()-start));
return result;
}
}
二、Spring容器深度解析
1. Bean生命周期全流程
1. 实例化 → 2. 属性填充 → 3. BeanNameAware → 4. BeanFactoryAware ↓ 5. PreInitialization(BeanPostProcessor) → 6. @PostConstruct ↓ 7. InitializingBean → 8. 自定义init-method → 9. PostInitialization
2. 作用域对比实验
@Scope("prototype")
@Bean
public PrototypeBean pb() { return new PrototypeBean(); }
// 测试代码：
PrototypeBean b1 = context.getBean(PrototypeBean.class);
PrototypeBean b2 = context.getBean(PrototypeBean.class);
System.out.println(b1 == b2); // 输出false
3. 条件化配置
@Conditional(ProdEnvCondition.class)
@Bean
public DataSource prodDataSource() {
return new ProductionDataSource();
}
public class ProdEnvCondition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
return "prod".equals(context.getEnvironment().getProperty("env"));
}
}
三、Spring MVC全流程剖析
1. 请求处理时序图
HTTP Request → DispatcherServlet → HandlerMapping → Controller → ModelAndView → ViewResolver → View → HTTP Response
2. 控制器开发模式
2.1 传统控制器
@Controller
@RequestMapping("/users")
public class UserController {
@GetMapping("/{id}")
public String getUser(@PathVariable Long id, Model model) {
model.addAttribute("user", userService.findById(id));
return "userDetail";
}
}
2.2 RESTful风格
@RestController
@RequestMapping("/api/users")
public class UserApiController {
@PostMapping
public ResponseEntity createUser(@RequestBody @Valid User user) {
User saved = userService.save(user);
URI location = ServletUriComponentsBuilder.fromCurrentRequest()
.path("/{id}").buildAndExpand(saved.getId()).toUri();
return ResponseEntity.created(location).body(saved);
}
}
3. 异常处理机制
@ControllerAdvice
public class GlobalExceptionHandler {
@ExceptionHandler(DataNotFoundException.class)
@ResponseStatus(HttpStatus.NOT_FOUND)
public ErrorResponse handleNotFound(DataNotFoundException ex) {
return new ErrorResponse("NOT_FOUND", ex.getMessage());
}
@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity> handleValidationExceptions(
MethodArgumentNotValidException ex) {
Map errors = new HashMap<>();
ex.getBindingResult().getAllErrors().forEach(error -> {
String fieldName = ((FieldError) error).getField();
errors.put(fieldName, error.getDefaultMessage());
});
return ResponseEntity.badRequest().body(errors);
}
}