情况 前端 String 后端 enum

前端

后端

报错

2024-05-31T21:47:40.618+08:00  WARN 21360 --- [nio-8080-exec-6] .w.s.m.s.DefaultHandlerExceptionResolver : 
Resolved [org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: 
Failed to convert value of type 'java.lang.String' to required type 'com.orchids.springmybatisplus.model.enums.Sex'; 
Failed to convert from type 
[java.lang.String] to type [@org.springframework.web.bind.annotation.RequestParam 
com.orchids.springmybatisplus.model.enums.Sex] for value '1']

问题出现在这个方法

    //根据性别查询学生 存在String --->转换为enums\@Operation(summary = "根据性别(类型)查询学生信息")@GetMapping("sex") //@RequestParam(required = false) required=false 表示参数可以没有public Result<List<Student>> StudentBySex(@RequestParam(required = false) Sex sex){LambdaQueryWrapper<Student> lambdaQueryWrapper = new LambdaQueryWrapper<>();lambdaQueryWrapper.eq(Student::getSex,sex);List<Student> list = studentService.list(lambdaQueryWrapper);return Result.ok(list);}

对应的枚举类

package com.orchids.springmybatisplus.model.enums;import com.baomidou.mybatisplus.annotation.EnumValue;
import com.fasterxml.jackson.annotation.JsonValue;/*** @Author qwh* @Date 2024/5/31 19:13*/
public enum Sex implements BaseEnum{MAN(0,"男性"),WOMAN(1, "女性");@EnumValue@JsonValueprivate Integer code;private String name;Sex(Integer code, String name) {this.code = code;this.name = name;}@Overridepublic Integer getCode() {return this.code;}@Overridepublic String getName() {return this.name;}
}

解决方法 一

1. 编写StringToSexConverter方法

package com.orchids.lovehouse.web.admin.custom.converter;import com.orchids.lovehouse.model.enums.ItemType;
import org.springframework.core.convert.converter.Converter;
import org.springframework.stereotype.Component;@Component
public class StringToItemTypeConverter implements Converter<String, ItemType> {/*** 根据给定的代码字符串转换为对应的ItemType枚举。** @param code 代表ItemType枚举的代码字符串，该代码应该是整数形式。* @return 对应于给定代码的ItemType枚举值。* @throws IllegalArgumentException 如果给定的代码无法匹配到任何枚举值时抛出。*/@Overridepublic ItemType convert(String code) {// 遍历所有ItemType枚举值，查找与给定代码匹配的枚举for (ItemType value : ItemType.values()) {if (value.getCode().equals(Integer.valueOf(code))) {return value;}}// 如果没有找到匹配的枚举，抛出异常throw new IllegalArgumentException("code非法");}
}

将其注册到WebMvcConfiguration

package com.orchids.springmybatisplus.web.custom.config;import com.orchids.springmybatisplus.web.custom.converter.StringToSexConverter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.format.FormatterRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;/*** @Author qwh* @Date 2024/5/31 22:06*/
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {@Autowiredprivate StringToSexConverter stringToItemTypeConverter;@Overridepublic void addFormatters(FormatterRegistry registry) {registry.addConverter(this.stringToItemTypeConverter);}
}

成功解决

2. 当有很多种类型需要转换 例如`
   1. String到Integer`、
   2. String到Date，
   3. String到Boolean
   • 就要写每一种转换方法 代码重用性不高
   • 于是就有了第二种方法
   • 使用[ConverterFactory](https://docs.spring.io/spring-framework/reference/core/validation/convert.html#core-convert-ConverterFactory-SPI)接口更为合适，这个接口可以将同一个转换逻辑应用到一个接口的所有实现类，因此我们可以定义一个BaseEnum接口，然后另所有的枚举类都实现该接口，然后就可以自定义ConverterFactory，集中编写各枚举类的转换逻辑了
   • 具体实现如下
   • 在编写一个BaseEnum接口

public interface BaseEnum {Integer getCode();String getName();
}

• 让enums 包下的枚举都实现这个接口

package com.orchids.springmybatisplus.model.enums;import com.baomidou.mybatisplus.annotation.EnumValue;
import com.fasterxml.jackson.annotation.JsonValue;/*** @Author qwh* @Date 2024/5/31 19:13*/
public enum Sex implements BaseEnum{MAN(0,"男性"),WOMAN(1, "女性");@EnumValue@JsonValueprivate Integer code;private String name;Sex(Integer code, String name) {this.code = code;this.name = name;}@Overridepublic Integer getCode() {return this.code;}@Overridepublic String getName() {return this.name;}
}

• 编写 StringToBaseEnumConverterFactory 实现接口 ConverterFactory

@Component
public class StringToBaseEnumConverterFactory implements ConverterFactory<String, BaseEnum> {@Overridepublic <T extends BaseEnum> Converter<String, T> getConverter(Class<T> targetType) {return new Converter<String, T>() {@Overridepublic T convert(String source) {for (T enumConstant : targetType.getEnumConstants()) {if (enumConstant.getCode().equals(Integer.valueOf(source))) {return enumConstant;}}throw new IllegalArgumentException("非法的枚举值:" + source);}};}
}

• 将其注册到WebMvcConfiguration

package com.orchids.springmybatisplus.web.custom.config;import com.orchids.springmybatisplus.web.custom.converter.StringToBaseEnumConverterFactory;
import com.orchids.springmybatisplus.web.custom.converter.StringToSexConverter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.format.FormatterRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;/*** @Author qwh* @Date 2024/5/31 22:06*/
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {@Autowiredprivate StringToBaseEnumConverterFactory stringToBaseEnumConverterFactory;@Overridepublic void addFormatters(FormatterRegistry registry) {registry.addConverterFactory(this.stringToBaseEnumConverterFactory);}
}

第二种方法有这一个类就行了