How to solve the problem that java only returns some fields in the entity class

How to return only some fields in the entity class

Add annotations on the entity class

@JsonInclude(JsonInclude.Include.NON_EMPTY)

Indicates that null, empty strings, empty collection arrays, etc. in the entity class will not be Serialization, that is, fields and values ​​will not be returned.

The following is an introduction to all values ​​​​of annotations

ALWAYS // 默认策略，任何情况都执行序列化
NON_NULL // 非空
NON_ABSENT // null的不会序列化，但如果类型是AtomicReference，依然会被序列化
NON_EMPTY // null、集合数组等没有内容、空字符串等，都不会被序列化
NON_DEFAULT // 如果字段是默认值，就不会被序列化
CUSTOM // 此时要指定valueFilter属性，该属性对应一个类，用来自定义判断被JsonInclude修饰的字段是否序列化
USE_DEFAULTS // 当JsonInclude在类和属性上都有时，优先使用属性上的注解，此时如果在序列化的get方法上使用了JsonInclude，并设置为USE_DEFAULTS，就会使用类注解的设置

java dynamically adds entity class fields and returns them to the front end

Tool class

package com.bless.wms.utils;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.beanutils.PropertyUtilsBean;
import org.springframework.cglib.beans.BeanGenerator;
import org.springframework.cglib.beans.BeanMap;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;
/**
 * 动态添加实体类字段
 */
@Slf4j
public final class PropertyAppender {
    private static final class DynamicBean {
        private Object target;
        private BeanMap beanMap;
        private DynamicBean(Class superclass, Map<String, Class> propertyMap) {
            this.target = generateBean(superclass, propertyMap);
            this.beanMap = BeanMap.create(this.target);
        }
        private void setValue(String property, Object value) {
            beanMap.put(property, value);
        }
        private Object getValue(String property) {
            return beanMap.get(property);
        }
        private Object getTarget() {
            return this.target;
        }
        /**
         * 根据属性生成对象
         */
        private Object generateBean(Class superclass, Map<String, Class> propertyMap) {
            BeanGenerator generator = new BeanGenerator();
            if (null != superclass) {
                generator.setSuperclass(superclass);
            }
            BeanGenerator.addProperties(generator, propertyMap);
            return generator.create();
        }
    }
    public static Object generate(Object dest, Map<String, Object> newValueMap) throws InvocationTargetException, IllegalAccessException {
        PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
        //1.获取原对象的字段数组
        PropertyDescriptor[] descriptorArr = propertyUtilsBean.getPropertyDescriptors(dest);
        //2.遍历原对象的字段数组，并将其封装到Map
        Map<String, Class> oldKeyMap = new HashMap<>();
        for (PropertyDescriptor it : descriptorArr) {
            if (!"class".equalsIgnoreCase(it.getName())) {
                oldKeyMap.put(it.getName(), it.getPropertyType());
                newValueMap.put(it.getName(), it.getReadMethod().invoke(dest));
            }
        }
        //3.将扩展字段Map合并到原字段Map中
        newValueMap.forEach((k, v) -> oldKeyMap.put(k, v.getClass()));
        //4.根据新的字段组合生成子类对象
        DynamicBean dynamicBean = new DynamicBean(dest.getClass(), oldKeyMap);
        //5.放回合并后的属性集合
        newValueMap.forEach((k, v) -> {
            try {
                dynamicBean.setValue(k, v);
            } catch (Exception e) {
                log.error("动态添加字段【值】出错", e);
            }
        });
        return dynamicBean.getTarget();
    }
}

Call

Front-end interface call test

Note: The front-end form can be dynamically rendered directly in a for loop

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