针对json数据格式不一致，使用注解对特殊的属性值处理

前提：近期使用高德一个接口，上了生产，才发现json里面的list实体，数据格式不一致。有数据的时候，数据为String类型，无数据的时候，数据为“[]”.（如图）

geocodes这个值里面，第一个list是正常的值，第二个list是个空值，但是前面有数据的定义为string，而第二个list定义为[]。那么在json转bean的时候，就会出现（图2）情况。

json转bean的时候，自动填充为值为“[]”。这样的数据保留是不满足业务需要的。

所以，可以制定一个注解，String类型的"[]"填充为 空字符串“”。List类型的属性就不需要理会。

代码如下：

实体：

package com.test.gaode003;

import lombok.Getter;
import lombok.Setter;

import java.util.List;

@Getter
@Setter
public class GaoDeEntity {

    private static final long serialVersionUID = -4506875151642772406L;
    private String status;

    private String info;

    private String infocode;

    private String count;


    private List<GeocodesEntity> geocodes;

}

package com.test.gaode003;

import lombok.Getter;
import lombok.Setter;

import java.util.List;

public @Getter
@Setter
class GeocodesEntity {

    private static final long serialVersionUID = 942508470576711519L;


    @ReflectTag
    private String formattedAddress;
    @ReflectTag
    private String country;
    @ReflectTag
    private String province;
    @ReflectTag
    private String citycode;
    @ReflectTag
    private String city;
    @ReflectTag
    private String district;

    private List<String> township;
    @ReflectTag
    private NeighborhoodDomain neighborhood;
    @ReflectTag
    private BuildingDomain building;
    @ReflectTag
    private String adcode;

    private List<String> street;

    private List<String> number;
    @ReflectTag
    private String location;
    @ReflectTag
    private String level;

    @Getter
    @Setter
    class NeighborhoodDomain {

        private static final long serialVersionUID = 7216259952414552319L;
        private List<String> name;

        private List<String> type;
    }

    @Getter
    @Setter
    class BuildingDomain {

        private static final long serialVersionUID = -4653848900240913579L;
        private List<String> name;

        private List<String> type;
    }
}

自定义注解：

package com.test.gaode003;


import java.lang.annotation.*;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
@Documented
public @interface ReflectTag {
}

测试：

package com.test.gaode003;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import org.apache.commons.io.FileUtils;

import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;

public class Test {


    @org.junit.Test
    public void test() throws IOException {
        String str = FileUtils.readFileToString(new File("C:\\workProject\\360\\test_data\\data\\test90.txt"), "UTF-8");


        GaoDeEntity GaoDeEntity = JSONObject.parseObject(str, GaoDeEntity.class);
        List<GeocodesEntity> geocodes = GaoDeEntity.getGeocodes();

        for (GeocodesEntity geocode : geocodes) {
            Class<? extends GeocodesEntity> clazz = geocode.getClass();
            Field[] fields = clazz.getDeclaredFields();
            for (Field field : fields) {
                if (field.isAnnotationPresent(ReflectTag.class)){
                    PropertyDescriptor propertyDescriptor = null;
                    try {
                        propertyDescriptor = new PropertyDescriptor(field.getName(), clazz);
                    } catch (IntrospectionException e) {
                        e.printStackTrace();
                    }
                    Method writeMethod = propertyDescriptor.getWriteMethod();
                    Method readMethod = propertyDescriptor.getReadMethod();
                    Object value = null;
                    try {
                        value = readMethod.invoke(geocode);

                        String s = value.toString();
                        if ("[]".equals(s.trim())) {
                            writeMethod.invoke(geocode,"");
                        }
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    } catch (InvocationTargetException e) {
                        e.printStackTrace();
                    }

                }
            }
        }

        System.out.println("geocodes:"+ JSON.toJSONString(geocodes));
    }
}

执行结果：String类型的都已经填充为"",List类型还是List类型

[{
	"adcode": "320117",
	"building": {
		"name": [],
		"type": []
	},
	"city": "南京市",
	"citycode": "025",
	"country": "中国",
	"district": "溧水区",
	"formattedAddress": "江苏省南京市溧水区永阳镇",
	"level": "乡镇",
	"location": "119.044331,31.659977",
	"neighborhood": {
		"name": ["南京市", "南京市", "南京市"],
		"type": []
	},
	"number": [],
	"province": "江苏省",
	"street": [],
	"township": []
}, {
	"adcode": "",
	"building": {
		"name": [],
		"type": []
	},
	"city": "",
	"citycode": "",
	"country": "",
	"district": "",
	"formattedAddress": "",
	"level": "",
	"location": "",
	"neighborhood": {
		"name": [],
		"type": []
	},
	"number": [],
	"province": "",
	"street": [],
	"township": []
}]

原始报文：test90.txt

{
    "status": "1",
    "info": "OK",
    "infocode": "10000",
    "count": "2",
    "geocodes": [
        {
            "formatted_address": "江苏省南京市溧水区永阳镇",
            "country": "中国",
            "province": "江苏省",
            "citycode": "025",
            "city": "南京市",
            "district": "溧水区",
            "township": [],
            "neighborhood": {
                "name": ["南京市","南京市","南京市"],
                "type": []
            },
            "building": {
                "name": [],
                "type": []
            },
            "adcode": "320117",
            "street": [],
            "number": [],
            "location": "119.044331,31.659977",
            "level": "乡镇"
        },
		{
            "formatted_address": [],
            "country": [],
            "province": [],
            "citycode": [],
            "city": [],
            "district": [],
            "township": [],
            "neighborhood": {
                "name": [],
                "type": []
            },
            "building": {
                "name": [],
                "type": []
            },
            "adcode": [],
            "street": [],
            "number": [],
            "location": [],
            "level": []
        }
    ]
}