Java为实体类动态添加属性的方法详解（java给实体类属性默认值）

目录添加依赖代码测试

可以给已有实体类动态的添加字段并返回新的实体对象，不影响原来的实体对象结构。

添加依赖

cglib

cglib

2.2.2

commons-beanutils

commons-beanutils

1.9.4

commons-beanutils

commons-beanutils

1.9.4

代码

import com.google.common.collect.Maps;

import net.sf.cglib.beans.BeanGenerator;

import net.sf.cglib.beans.BeanMap;

import org.apache.commons.beanutils.PropertyUtilsBean;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import java.beans.PropertyDescriptor;

import java.util.Map;

/**

* 动态为bean添加字段

* @Author gongl

* @Create 2022-01-11

*/

public class DynamicBeanUtils {

private static final Logger logger = LoggerFactory.getLogger(DynamicBeanUtils.class);

public static Object getTarget(Object dest, Map addProperties) {

PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();

//得到原对象的属性

PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(dest);

Map> propertyMap = Maps.newHashMap();

for (PropertyDescriptor d : descriptors) {

if (!"class".equalsIgnoreCase(d.http://getName())) {

propertyMap.put(d.getName(), d.getPropertyType());

}

}

addProperties.forEach((k, v) -> propertyMap.put(k, v.getClass()));

//构建新的对象

DynamicBean dynamicBean = new DynamicBean(dest.getClass(), propertyMap);

for (Map.Entry> entry : propertyMap.entrySet()) {

try {

if (!addProperties.containsKey(entry.getKey())) {//原来的值

dynamicBean.setValue(entry.getKey(), propertyUtilsBean.getNestedProperty(dest, entry.getKey()));

}else {//新增GukTADOguB的值

dynamicBean.setValue(entry.getKey(), addProperties.get(entry.getKey()));

}

} catch (Exception e) {

logger.error(e.getMessage(), e);

}

}

return dynamicBean.getTarget();

}

private static class DynamicBean {

/**

* 目标对象

*/

private Object target;

/**

* 属性集合

*/

private BeanMap beanMap;

public DynamicBean(Class> superclass, Map> propertyMap) {

this.target = generateBean(superclass, propertyMap);

this.beanMap = BeanMap.create(this.target);

}

/**

* bean 添加属性和值

*

* @param property

* @param value

*/

public void setValue(String property, Object value) {

beanMap.put(property, value);

}

/**

* 获取属性值

*

* @param property

* @return

*/

public Object getValue(String property) {

return beanMap.get(property);

}

/**

* 获取对象

*

* @return

*/

public Object getTarget() {

return this.target;

}

/**

* 根据属性生成对象

*

* @param superclass

* @param propertyMap

http:// * @return

*/

private Object generateBean(Class> superclass, Map> propertyMap) {

BeanGenerator generator = new BeanGenerator();

if (null != superclass) {

generator.setSuperclass(superclass);

}

BeanGenerator.addProperties(generator, propertyMap);

return generator.create();

}

}

}

测试

public static class TestBean{

private String name;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

}

public static void main(String[] args) throws InvocationTargetException, IllegalAccessException {

TestBean bean = new TestBean();

bean.setName("张三");

Map map = new HashMap<>();

map.put("age", 29);

//添加参数age--->29

Object obj = DynamicBeanUtils.getTarget(bean, map);

//打印结果

Method[] declaredMethods = obj.getClass().getDeclaredMethods();

for(Method method:declaredMethods){

if(method.getName().startsWith("get")){

Object o=method.invoke(obj);

System.out.println("属性值get方法->"+o);

}

}

}

结果打印出name和age的值

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