JAVA“动态”为类添加属性

最新推荐文章于 2025-06-20 13:40:27 发布

转载最新推荐文章于 2025-06-20 13:40:27 发布 · 1.9w 阅读

本文介绍了一种利用cglib和commons-beanutils库动态创建Java Bean的方法，并演示了如何扩展现有对象的属性，通过代码示例展示了具体的实现过程。

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来源： https://www.cnblogs.com/frinder6/p/7204574.html

部分参考：http://www.cnblogs.com/zy2009/p/6725843.html

pom.xml中添加：

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.3</version>
</dependency>
 
<dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib-nodep</artifactId>
    <version>3.2.4</version>
</dependency>

使用cglib动态生成类与使用 commons-beanutils获取源对象属性-类型集合，封装成新对象并设置值代码：

package com.frinder.util;
 
import com.google.common.collect.Maps;
import com.kiktech.entity.LoggerEntity;
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.HashMap;
import java.util.Map;
 
/**
 * Created by frinder on 2017/7/18.
 */
public class ReflectUtil {
 
    staticLogger logger = LoggerFactory.getLogger(ReflectUtil.class);
 
    publicstatic Object getTarget(Object dest, Map<String, Object> addProperties) {
        // get property map
        PropertyUtilsBean propertyUtilsBean =new PropertyUtilsBean();
        PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(dest);
        Map<String, Class> propertyMap = Maps.newHashMap();
        for(PropertyDescriptor d : descriptors) {
            if(!"class".equalsIgnoreCase(d.getName())) {
                propertyMap.put(d.getName(), d.getPropertyType());
            }
        }
        // add extra properties
        addProperties.forEach((k, v) -> propertyMap.put(k, v.getClass()));
        // new dynamic bean
        DynamicBean dynamicBean =new DynamicBean(dest.getClass(), propertyMap);
        // add old value
        propertyMap.forEach((k, v) -> {
            try{
                // filter extra properties
                if(!addProperties.containsKey(k)) {
                    dynamicBean.setValue(k, propertyUtilsBean.getNestedProperty(dest, k));
                }
            }catch (Exception e) {
                logger.error(e.getMessage(), e);
            }
        });
        // add extra value
        addProperties.forEach((k, v) -> {
            try{
                dynamicBean.setValue(k, v);
            }catch (Exception e) {
                logger.error(e.getMessage(), e);
            }
        });
        Object target = dynamicBean.getTarget();
        returntarget;
    }
 
 
    publicstatic void main(String[] args) {
        LoggerEntity entity =new LoggerEntity();
        entity.setAppName("appname");
        entity.setOperator("add");
        entity.setResult("result");
        entity.setUri("uri");
        entity.setMethod("method");
        Map<String, Object> addProperties =new HashMap() {{
            put("hello","world");
            put("abc","123");
        }};
        System.out.println(getTarget(entity, addProperties));
    }
 
 
    publicstatic class DynamicBean {
        /**
         * 目标对象
         */
        privateObject target;
 
        /**
         * 属性集合
         */
        privateBeanMap beanMap;
 
        publicDynamicBean(Class superclass, Map<String, Class> propertyMap) {
            this.target = generateBean(superclass, propertyMap);
            this.beanMap = BeanMap.create(this.target);
        }
 
 
        /**
         * bean 添加属性和值
         *
         * @param property
         * @param value
         */
        publicvoid setValue(String property, Object value) {
            beanMap.put(property, value);
        }
 
        /**
         * 获取属性值
         *
         * @param property
         * @return
         */
        publicObject getValue(String property) {
            returnbeanMap.get(property);
        }
 
        /**
         * 获取对象
         *
         * @return
         */
        publicObject getTarget() {
            returnthis.target;
        }
 
 
        /**
         * 根据属性生成对象
         *
         * @param superclass
         * @param propertyMap
         * @return
         */
        privateObject generateBean(Class superclass, Map<String, Class> propertyMap) {
            BeanGenerator generator =new BeanGenerator();
            if(null != superclass) {
                generator.setSuperclass(superclass);
            }
            BeanGenerator.addProperties(generator, propertyMap);
            returngenerator.create();
        }
    }
 
}

LoggerEntity代码：

package com.frinder.entity;
 
import net.logstash.logback.encoder.org.apache.commons.lang.builder.ReflectionToStringBuilder;
 
/**
 * Created by frinder on 2017/5/24.
 */
public class LoggerEntity {
 
    privateString method;
    privateString uri;
    privateObject[] args;
    privateObject result;
    privateString operator;
    privateString appName;
 
    /**
     * 获取当前对象
     *
     * @param method
     * @param uri
     * @param args
     * @param result
     * @return
     */
    publicLoggerEntity get(String method, String uri, Object[] args, Object result, String operator, String appName) {
        setMethod(method);
        setUri(uri);
        setArgs(args);
        setResult(result);
        setOperator(operator);
        setAppName(appName);
        returnthis;
    }
 
    publicString getMethod() {
        returnmethod;
    }
 
    publicvoid setMethod(String method) {
        this.method = method;
    }
 
    publicString getUri() {
        returnuri;
    }
 
    publicvoid setUri(String uri) {
        this.uri = uri;
    }
 
    publicObject[] getArgs() {
        returnargs;
    }
 
    publicvoid setArgs(Object[] args) {
        this.args = args;
    }
 
    publicObject getResult() {
        returnresult;
    }
 
    publicvoid setResult(Object result) {
        this.result = result;
    }
 
    publicString getOperator() {
        returnoperator;
    }
 
    publicvoid setOperator(String operator) {
        this.operator = operator;
    }
 
    publicString getAppName() {
        returnappName;
    }
 
    publicvoid setAppName(String appName) {
        this.appName = appName;
    }
 
    @Override
    publicString toString() {
        returnReflectionToStringBuilder.toString(this);
    }
}