问题

描述
接口的参数验证（比如：字段长度、字段需要符合某个格式）

解决思路

在控制器类的方法里自己写校验逻辑代码
找找是否有可用的第三方库

解决方案

1. 自己写逻辑

优点

足够自由,可以完全按照业务逻辑写
不需要额外引入第三方库

缺点

不够优雅
参数验证与业务逻辑本身关系不大，会占用大量精力
后期的维护成本高

2. 使用Bean Validation

1. PathVariable校验

直接将参数验证的条件加到参数后面，{group:\d{6}}表示参数group必须是6位的数据
示例

@RequestMapping(value = "pathVariableTest/{group:\\d{6}}/{userid}")
   public String pathVariableTest(@PathVariable("group") String group, @PathVariable("userid") Integer userid) {
       return "suc";
   }

访问一个错误路径，会得到404响应
结果

{
    "timestamp": "2020-10-19T09:29:12.950+00:00",
    "status": 404,
    "error": "Not Found",
    "message": "",
    "path": "/pathVariableTest/aAa/3"
}

注意：PathVariable 只有正则表达式可达到校验的目的，即只有正则表达式这一种验证方式。

2. RequestParam校验

在对应的参数上添加校验条件

 @RequestMapping(value = "requestParamTest")
    public String requestParamTest(
            @RequestParam @Size(min = 1, max = 10, message = "姓名长度必须为1到10") String name,
            @Min(value = 10, message = "年龄最小为10") @Max(value = 100, message = "年龄最大为100") @RequestParam("age") Integer age) {
        return "suc";
    }

声明MethodValidationPostProcessor

注意：这一步是为了要启用RequestParam校验

@Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
        return new MethodValidationPostProcessor();
    }

Controller指定@Validated注解

注意：一定要在Ctroller类上，不然校验条件也是无法生效的。

 @RequestMapping(value = "requestParamTest")
    public String requestParamTest(
            @RequestParam @Size(min = 1, max = 10, message = "姓名长度必须为1到10") String name,
            @Min(value = 10, message = "年龄最小为10") @Max(value = 100, message = "年龄最大为100") @RequestParam("age") Integer age) {
        return "suc";
    }

尝试使用非法值访问
结果

{
    "timestamp": "2020-10-19T10:07:44.509+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "message": "",
    "path": "/requestParamTest"
}

2020-10-19 17:42:13.424 ERROR 21660 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is javax.validation.ConstraintViolationException: requestParamTest.age: 年龄最大为100] with root cause

javax.validation.ConstraintViolationException: requestParamTest.age: 年龄最大为100
    at org.springframework.validation.beanvalidation.MethodValidationInterceptor.invoke(MethodValidationInterceptor.java:116) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at com.hyq.demo.springbootdemo.ParamValidController$$EnhancerBySpringCGLIB$$293abf03.requestParamTest() ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
    ...

3.RequestBody验证

对于直接JSON消息体传参，同样可以定义校验规则

在接口上设置参数校验

注意：必须要将将注解Validated设置在参数上，在Ctroller类上的设置对RequestBody的校验无效

@RequestMapping(value = "requestBodyTest")
    public String requestBodyTest(@Validated @RequestBody User user) {
        return "suc";
    }

在RequestBody对应的Bean上设置校验条件

public class User {
    @Size(min = 1, max = 10, message = "姓名长度必须为1到10")
    private String name;

    @Min(value = 10, message = "年龄最小为10")
    @Max(value = 100, message = "年龄最大为100")
    private int age;
}

尝试使用非法值访问
结果

{
    "timestamp": "2020-10-19T10:00:29.682+00:00",
    "status": 400,
    "error": "Bad Request",
    "message": "",
    "path": "/requestBodyTest"
}

2020-10-19 18:00:29.673  WARN 22448 --- [nio-8080-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument [0] in public java.lang.String com.hyq.demo.springbootdemo.ParamValidController.requestBodyTest(com.hyq.demo.springbootdemo.User): [Field error in object 'user' on field 'age': rejected value [192]; codes [Max.user.age,Max.age,Max.int,Max]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [user.age,age]; arguments []; default message [age],100]; default message [年龄最大为100]] ]

4.表单对象校验

参考链接

参考文章

springboot 参数校验详解
SpringBoot里参数校验/参数验证

Spring-boot参数校验：基本用法

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