Java反射机制笔记

package com.circle.core.util;

import com.circle.core.utilv2.CheckUtils;
import com.circle.test.controller.TestAnnotaion;
import com.dcc.common.entity.IInterfileEntity;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

/**
 * @author tianming.fan
 *
 */
public class BeanHelper {
	
	public static void main(String[] args) {
		IInterfileEntity obj = new IInterfileEntity();
		obj.setId("123123");
		obj.setUserName("dfdsfdsfsda");
		obj.setTitle("");
		try {
			//System.out.println(checkBeanAttr(obj));
		} catch (Exception e) {
			e.printStackTrace();
		}
		//System.out.println("end");
	}
	public static void main2(String[] args) {
		Map<String, String> tipMap = new HashMap<String, String>();
		//System.out.println(tipMap.get("as"));
	}
	
	/**
     *
	 * 检查对象属性的必填项检查方法
	 * tianming.fan
	 * @param bean 对象
	 * @return 检查通过返回空字符串
	 * @throws Exception
	 */
	public static String checkBeanAttr(Object bean) throws Exception{
		if (null != bean) {
			//获取所有的字段包括public,private,protected,private
			
            Field[] fields = bean.getClass().getDeclaredFields();
			//Field[] fields = bean.getClass().getFields();
			//System.out.println("fields:"+fields.length);
            for (int i = 0; i < fields.length; i++) {
                Field field = fields[i];
                //System.out.println("Key"+i+":"+field.getName());
                if ("java.lang.String".equals(field.getType().getName())) {
                	String key = field.getName();//获取字段名
                	Object value = getFieldValue(bean, key);
                    if (CheckUtils.checkIsNull(value)) {
                    	//判断字段是否为必填
                    	Map<String, Boolean> requiredMap = (Map<String, Boolean>)getFieldValue(bean, "requiredMap");
                    	if (!requiredMap.get(key)) {
                    		continue;
						}
                    	try {
                        	Map<String, String> tipMap = (Map<String, String>)getFieldValue(bean, "tipMap");
                        	String tipMsg = tipMap.get(key);
                            return tipMsg;
						} catch (Exception e) {
							return key+"不能为空";
						}
                    
                    }
                }
            }
		}
		
		return "";
	}
	/**/
	
	
	/**
     * 去掉bean中所有属性为字符串的前后空格
     * @param bean
     * @throws Exception
     */
    public static void beanAttributeValueTrim(Object bean) throws Exception {
        if(bean!=null){
            //获取所有的字段包括public,private,protected,private
            Field[] fields = bean.getClass().getDeclaredFields();
            for (int i = 0; i < fields.length; i++) {
                Field f = fields[i];
                if (f.getType().getName().equals("java.lang.String")) {
                    String key = f.getName();//获取字段名
                    Object value = getFieldValue(bean, key);
                    if (value == null) {
                        continue;
                    }
                    
                    setFieldValue(bean, key, value.toString().trim());
                }
            }
        }
    }

    //=============================================================================
    /**
     * 利用反射通过get方法获取bean中字段fieldName的值
     * @param bean
     * @param fieldName
     * @return
     * @throws Exception
     */
    private static Object getFieldValue(Object bean, String fieldName)
            throws Exception {
        StringBuffer result = new StringBuffer();
        String methodName = result.append("get")
                .append(fieldName.substring(0, 1).toUpperCase())
                .append(fieldName.substring(1)).toString();

        Object rObject = null;
        Method method = null;

        @SuppressWarnings("rawtypes")
        Class[] classArr = new Class[0];
        method = bean.getClass().getMethod(methodName, classArr);
        rObject = method.invoke(bean, new Object[0]);

        return rObject;
    }

    /**
     * 利用发射调用bean.set方法将value设置到字段
     * @param bean
     * @param fieldName
     * @param value
     * @throws Exception
     */
    private static void setFieldValue(Object bean, String fieldName, Object value)
            throws Exception {
        StringBuffer result = new StringBuffer();
        String methodName = result.append("set")
                .append(fieldName.substring(0, 1).toUpperCase())
                .append(fieldName.substring(1)).toString();

        /**
         * 利用发射调用bean.set方法将value设置到字段
         */
        Class[] classArr = new Class[1];
        classArr[0]="java.lang.String".getClass();
        Method method=bean.getClass().getMethod(methodName,classArr);
        method.invoke(bean,value);
    }
    
    //-----------------------
    /**
     * @Author Nxy
     * @Date 2020/2/15 14:14
     * @Description 汇总加减分原因
     */
    public static void setMarkReasons(Object bean) throws Exception {
        Class beanClass = bean.getClass();
        Field[] fields = beanClass.getDeclaredFields();
        if (fields == null || fields.length == 0) {
            throw new RuntimeException(bean + " has no field");
        }
        //Field targetField = beanClass.getDeclaredField("markReasons");
        //遍历属性
        for (Field field : fields) {//判断该属性是否被　MarkReason  注解修饰
            if (field.isAnnotationPresent(TestAnnotaion.class)) {
                //允许私有属性访问
                field.setAccessible(true);
                TestAnnotaion reasonAnno = field.getAnnotation(TestAnnotaion.class);
                
                //拼装加减分原因
                String value = reasonAnno.value().toString().trim();
                //System.out.println("value: "+value);
                setFieldValue(bean, field.getName(), value);
                //reasonsSb.append();
            }
        }
        
    }
}

  private Object instantiateHandler(String className)
  {
    Class<?> handlerClass = null;
    Object handler = null;
    try
    {
      handlerClass = Class.forName(className);
    }
    catch (ClassNotFoundException e)
    {
    }
    catch (Throwable e1)
    {
    }

    if (handlerClass != null)
    {
      try
      {
        handler = handlerClass.newInstance();
      }
      catch (IllegalAccessException e)
      {
      }
      catch (InstantiationException e)
      {
      }
    }
    return handler;
  }

package org.jeecgframework.core.util;

import org.apache.commons.beanutils.DynaBean;
import org.apache.commons.beanutils.DynaProperty;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.beanutils.PropertyUtilsBean;

import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.util.Iterator;
import java.util.Map;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * @author  张代浩
 * @version 1.0
 */

public class MyBeanUtils
    extends PropertyUtilsBean {

  private static void convert(Object dest, Object orig) throws
      IllegalAccessException, InvocationTargetException {

      // Validate existence of the specified beans
      if (dest == null) {
          throw new IllegalArgumentException
              ("No destination bean specified");
      }
      if (orig == null) {
          throw new IllegalArgumentException("No origin bean specified");
      }

      // Copy the properties, converting as necessary
      if (orig instanceof DynaBean) {
          DynaProperty origDescriptors[] =
              ( (DynaBean) orig).getDynaClass().getDynaProperties();
          for (int i = 0; i < origDescriptors.length; i++) {
              String name = origDescriptors[i].getName();
              if (PropertyUtils.isWriteable(dest, name)) {
                  Object value = ( (DynaBean) orig).get(name);
                  try {
                	  getInstance().setSimpleProperty(dest, name, value);
                  }
                  catch (Exception e) {
                      ; // Should not happen
                  }

              }
          }
      }
      else if (orig instanceof Map) {
          Iterator names = ( (Map) orig).keySet().iterator();
          while (names.hasNext()) {
              String name = (String) names.next();
              if (PropertyUtils.isWriteable(dest, name)) {
                  Object value = ( (Map) orig).get(name);
                  try {
                	  getInstance().setSimpleProperty(dest, name, value);
                  }
                  catch (Exception e) {
                      ; // Should not happen
                  }

              }
          }
      }
      else
      /* if (orig is a standard JavaBean) */
      {
          PropertyDescriptor origDescriptors[] =
              PropertyUtils.getPropertyDescriptors(orig);
          for (int i = 0; i < origDescriptors.length; i++) {
              String name = origDescriptors[i].getName();
//              String type = origDescriptors[i].getPropertyType().toString();
              if ("class".equals(name)) {
                  continue; // No point in trying to set an object's class
              }
              if (PropertyUtils.isReadable(orig, name) &&
                  PropertyUtils.isWriteable(dest, name)) {
                  try {
                      Object value = PropertyUtils.getSimpleProperty(orig, name);
                      getInstance().setSimpleProperty(dest, name, value);
                  }
                  catch (java.lang.IllegalArgumentException ie) {
                      ; // Should not happen
                  }
                  catch (Exception e) {
                      ; // Should not happen
                  }

              }
          }
      }

  }

  
  /**
	 * 对象拷贝
	 * 数据对象空值不拷贝到目标对象
	 * 
	 * @param databean
	 * @param tobean
	 * @throws NoSuchMethodException
	 * copy
	 */
  public static void copyBeanNotNull2Bean(Object databean,Object tobean)throws Exception
  {
	  PropertyDescriptor origDescriptors[] = PropertyUtils.getPropertyDescriptors(databean);
      for (int i = 0; i < origDescriptors.length; i++) {
          String name = origDescriptors[i].getName();
//          String type = origDescriptors[i].getPropertyType().toString();
          if ("class".equals(name)) {
              continue; // No point in trying to set an object's class
          }
          if (PropertyUtils.isReadable(databean, name) &&PropertyUtils.isWriteable(tobean, name)) {
              try {
                  Object value = PropertyUtils.getSimpleProperty(databean, name);
                  if(value!=null){
                	  getInstance().setSimpleProperty(tobean, name, value);
                  }
              }
              catch (java.lang.IllegalArgumentException ie) {
                  ; // Should not happen
              }
              catch (Exception e) {
                  ; // Should not happen
              }

          }
      }
  }
  
  
  /**
   * 把orig和dest相同属性的value复制到dest中
   * @param dest
   * @param orig
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static void copyBean2Bean(Object dest, Object orig) throws Exception {
      convert(dest, orig);
  }

  public static void copyBean2Map(Map map, Object bean){
	PropertyDescriptor[] pds = PropertyUtils.getPropertyDescriptors(bean);
	for (int i =0;i<pds.length;i++)
	{
		PropertyDescriptor pd = pds[i];
		String propname = pd.getName();
		try {
			Object propvalue = PropertyUtils.getSimpleProperty(bean,propname);
			map.put(propname, propvalue);
		} catch (IllegalAccessException e) {
			//e.printStackTrace();
		} catch (InvocationTargetException e) {
			//e.printStackTrace();
		} catch (NoSuchMethodException e) {
			//e.printStackTrace();
		}
	}
  }

  /**
   * 将Map内的key与Bean中属性相同的内容复制到BEAN中
   * @param bean Object
   * @param properties Map
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static void copyMap2Bean(Object bean, Map properties) throws
      IllegalAccessException, InvocationTargetException {
      // Do nothing unless both arguments have been specified
      if ( (bean == null) || (properties == null)) {
          return;
      }
      // Loop through the property name/value pairs to be set
      Iterator names = properties.keySet().iterator();
      while (names.hasNext()) {
          String name = (String) names.next();
          // Identify the property name and value(s) to be assigned
          if (name == null) {
              continue;
          }
          Object value = properties.get(name);
          try {
              Class clazz = PropertyUtils.getPropertyType(bean, name);
              if (null == clazz) {
                  continue;
              }
              String className = clazz.getName();
              if (className.equalsIgnoreCase("java.sql.Timestamp")) {
                  if (value == null || value.equals("")) {
                      continue;
                  }
              }
              getInstance().setSimpleProperty(bean, name, value);
          }
          catch (NoSuchMethodException e) {
              continue;
          }
      }
  }
  

  /**
   * 自动转Map key值大写
   * 将Map内的key与Bean中属性相同的内容复制到BEAN中
   * @param bean Object
   * @param properties Map
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static void copyMap2Bean_Nobig(Object bean, Map properties) throws
      IllegalAccessException, InvocationTargetException {
      // Do nothing unless both arguments have been specified
      if ( (bean == null) || (properties == null)) {
          return;
      }
      // Loop through the property name/value pairs to be set
      Iterator names = properties.keySet().iterator();
      while (names.hasNext()) {
          String name = (String) names.next();
          // Identify the property name and value(s) to be assigned
          if (name == null) {
              continue;
          }
          Object value = properties.get(name);
          // 命名应该大小写应该敏感(否则取不到对象的属性)
          //name = name.toLowerCase();
          try {
        	  if (value == null) {	// 不光Date类型，好多类型在null时会出错
                  continue;	// 如果为null不用设 (对象如果有特殊初始值也可以保留？)
              }
              Class clazz = PropertyUtils.getPropertyType(bean, name);
              if (null == clazz) {	// 在bean中这个属性不存在
                  continue;
              }
              String className = clazz.getName();
              // 临时对策（如果不处理默认的类型转换时会出错）
              if (className.equalsIgnoreCase("java.util.Date")) {
                  value = new java.util.Date(((java.sql.Timestamp)value).getTime());// wait to do：貌似有时区问题, 待进一步确认
              }
//              if (className.equalsIgnoreCase("java.sql.Timestamp")) {
//                  if (value == null || value.equals("")) {
//                      continue;
//                  }
//              }
              getInstance().setSimpleProperty(bean, name, value);
          }
          catch (NoSuchMethodException e) {
              continue;
          }
      }
  }

  /**
   * Map内的key与Bean中属性相同的内容复制到BEAN中
   * 对于存在空值的取默认值
   * @param bean Object
   * @param properties Map
   * @param defaultValue String
   * @throws IllegalAccessException
   * @throws InvocationTargetException
   */
  public static void copyMap2Bean(Object bean, Map properties, String defaultValue) throws
      IllegalAccessException, InvocationTargetException {
      // Do nothing unless both arguments have been specified
      if ( (bean == null) || (properties == null)) {
          return;
      }
      // Loop through the property name/value pairs to be set
      Iterator names = properties.keySet().iterator();
      while (names.hasNext()) {
          String name = (String) names.next();
          // Identify the property name and value(s) to be assigned
          if (name == null) {
              continue;
          }
          Object value = properties.get(name);
          try {
              Class clazz = PropertyUtils.getPropertyType(bean, name);
              if (null == clazz) {
                  continue;
              }
              String className = clazz.getName();
              if (className.equalsIgnoreCase("java.sql.Timestamp")) {
                  if (value == null || value.equals("")) {
                      continue;
                  }
              }
              if (className.equalsIgnoreCase("java.lang.String")) {
                  if (value == null) {
                      value = defaultValue;
                  }
              }
              getInstance().setSimpleProperty(bean, name, value);
          }
          catch (NoSuchMethodException e) {
              continue;
          }
      }
  }
  
  public MyBeanUtils() {
    super();
  }
}