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 tipMap = new HashMap();
//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 requiredMap = (Map)getFieldValue(bean, "requiredMap");
if (!requiredMap.get(key)) {
continue;
}
try {
Map tipMap = (Map)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;
/**
* Title:
* Description:
* @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