ssm（3-2）Springmvc拓展

1.rest风格

2.@Pathvariable注解

2.1配置正则实例

@AllArgsConstructor
@NoArgsConstructor
@Data
@Accessors(chain = true)  //lombok
public class User implements Serializable {
    private  String  name;
}

@RestController   //responsebody +controller
public class UserController {
    @GetMapping("/user/{name:.*}")   
    public User  testUser(@PathVariable(required = false,value = "name") User user){
        System.out.println(user.getClass());
        return  user;
    }
}

@SpringBootApplication
public class MvcDemoApplication  {

    public static void main(String[] args) {
        SpringApplication.run(MvcDemoApplication.class, args);
    }
}

@Configuration
@ComponentScan(value = "springmvc.demo")//扫描包
public class MVCConfig  {

}

spring.http.encoding.charset=UTF-8  #处理编码
spring.http.encoding.force=true
spring.http.encoding.enabled=true
server.tomcat.uri-encoding=UTF-8

3.@valid与@Validated

@valid与@Validated的区别，@Validated是spring中的，是在@valid基础上而来的，在@valid的基础上增加分组功能，这里就直接说@Validated，没有加分组都需要认证，加了分组只有符合分组的才需要认证，一般不使用分组

3.1基本使用

@AllArgsConstructor
@NoArgsConstructor
@Data
@Accessors(chain = true)
public class User implements Serializable {
    @NotNull(message="不能为空")//含有属性groups
    private  String  name;
}

@RestController
public class UserController {
    @GetMapping("/user")
    public User  testUser(@Validated User user, BindingResult  result){
        result.getAllErrors().stream().forEach((x)->{
            System.out.println(x.getObjectName()+":"+x.getDefaultMessage());
        });
        System.out.println(user.getClass());
        return  user;
    }
}

输出结果：user:不能为空

备注：假如没有BindingResult result，那么在进入testUser之前就会被拦截，message="不能为空"并没有什么作用，加入BindingResult result之后，才会进入testUser方法，在没有进入方法时的异常页面见后该篇4

3.2自定义符合valid的注解

这里定义的是@NoNull注解

//会自动加载，不需要其他的配置
public class MyValidAnnotation implements ConstraintValidator<MyNotNull,Object> {
    /*
    obj:需要验证的参数
     */
    @Override
    public boolean isValid(Object obj, ConstraintValidatorContext constraintValidatorContext) {
        System.out.println(obj);
        return false;
    }

    @Override
    public void initialize(MyNotNull constraintAnnotation) {

    }
}

@Target({ElementType.METHOD, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy =MyValidAnnotation.class )
public @interface MyNotNull {
    String message() default "{javax.validation.constraints.NotNull.message}";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

@AllArgsConstructor
@NoArgsConstructor
@Data
@Accessors(chain = true)
public class User implements Serializable {
    @MyNotNull(message="不能为空---MyNotNull")
    private  String  name;
}

@RestController
public class UserController {
    @GetMapping("/user")
    public User  testUser(@Validated User user, BindingResult  result){
        result.getAllErrors().stream().forEach((x)->{
            System.out.println(x.getObjectName()+":"+x.getDefaultMessage());
        });
        return  user;
    }
}

4.异常消息的处理

4.1验证异常消息的处理上述已经说明

4.2直接被拦截的异常处理

springboot会相应的转向我们在resources下新建的resources的error的相应的错误代码的页面

还可以是如下这样，表示以4开头的错误页面

4.3运行过程中出现的异常

4.3.1直接抛出异常

@GetMapping("/user/error")
    public User  testUser1(@Validated User user, BindingResult  result) throws Exception {
        throw  new Exception("出错了");
    }

4.3.2 throw自定义异常类

@ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR,reason = "内部出错了！")
public class MyException extends RuntimeException {
}

 @GetMapping("/user/error")
    public User  testUser1(@Validated User user, BindingResult  result) throws Exception {
        throw  new MyException();
    }

4.3.3 使用@ExceptionHandler注解

  @ResponseBody
    @GetMapping("/testExceptionHandler")
    public User  testUser1(@Validated User user, BindingResult  result) throws Exception {
        int  i=10/0;
        return user;
    }

@ExceptionHandler({Exception.class})
    public String  testExceptionHandler(){
        return   "redirect:/error.html"; //重定向
    }

4.3.4 修改状态码及原因，@ResponseStatus也能在

　　 @ExceptionHandler({Exception.class})
    @ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR,reason = "内部错误")
    public void  testExceptionHandler(){
    }

备注：这样之后不会去相应的页面，也就是加入有返回值例如return "redirect:/error.html";，会失效

4.3.5@ControllerAdvice定制全局的异常，类中的@ExceptionHandler优先级高于@ControllerAdvice中的@ExceptionHandler优先级

@ControllerAdvice
public class MyExceptionHandler {
    @ExceptionHandler({Exception.class})
    @ResponseStatus(value = HttpStatus.INTERNAL_SERVER_ERROR,reason = "内部错误")
    public void  testExceptionHandler(){
    }
}

5.jsonview

ssm（3-2）Springmvc拓展

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