SpringBoot 统一 NULL转为空字符

https://blog.csdn.net/hellojoy/article/details/106943104

package com.toyor.hpqsharecloud.common;

import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Null2EmptyString {

/*
取Bean的属性和值对应关系的MAP
* @param __bean
* @return Map
*/
public static Map getFieldValueMap(Object bean) {
Class<?> cls = bean.getClass();
Map valueMap = new HashMap();
_// 取出bean里的所有方法
_Method[] methods = cls.getDeclaredMethods();
Field[] fields = cls.getDeclaredFields();

  **for **(Field field : fields) {<br />         **try **{<br />            String fieldType = field.getType().getSimpleName();<br />            String fieldGetName = _parGetName_(field.getName());<br />            **if **(!_checkGetMet_(methods, fieldGetName)) {<br />               **continue**;<br />            }<br />            Method fieldGetMet = cls.getMethod(fieldGetName, **new **Class[] {});<br />            Object fieldVal = fieldGetMet.invoke(bean, **new **Object[] {});<br />            String result = **null**;<br />            _/*if ("Date".equals(fieldType)) {<br />               result = fmtDate((Date) fieldVal);<br />            } else {<br />               if (null != fieldVal) {<br />                  result = String.valueOf(fieldVal);<br />               }<br />            }*/<br />            _valueMap.put(field.getName(), result);<br />         } **catch **(Exception e) {<br />            **continue**;<br />         }<br />      }<br />      **return **valueMap;

}

public static void setFieldValue(Object bean) {
Class<?> cls = bean.getClass();
_// 取出bean里的所有方法
_Method[] methods = cls.getDeclaredMethods();
Field[] fields = cls.getDeclaredFields();

  **for **(Field field : fields) {<br />         **try **{<br />            String fieldSetName = _parSetName_(field.getName());<br />            **if **(!_checkSetMet_(methods, fieldSetName)) {<br />               **continue**;<br />            }<br />            Method fieldSetMet = cls.getMethod(fieldSetName, field.getType());<br />            _/*String value = valMap.get(field.getName());<br />            if (null != value && !"".equals(value)) {<br />               String fieldType = field.getType().getSimpleName();<br />               if ("String".equals(fieldType)) {<br />                  fieldSetMet.invoke(bean, value);<br />               } else if ("Date".equals(fieldType)) {<br />                  Date temp = parseDate(value);<br />                  fieldSetMet.invoke(bean, temp);<br />               } else if ("Integer".equals(fieldType) || "int".equals(fieldType)) {<br />                  Integer intval = Integer.parseInt(value);<br />                  fieldSetMet.invoke(bean, intval);<br />               } else if ("Long".equalsIgnoreCase(fieldType)) {<br />                  Long temp = Long.parseLong(value);<br />                  fieldSetMet.invoke(bean, temp);<br />               } else if ("Double".equalsIgnoreCase(fieldType)) {<br />                  Double temp = Double.parseDouble(value);<br />                  fieldSetMet.invoke(bean, temp);<br />               } else if ("Boolean".equalsIgnoreCase(fieldType)) {<br />                  Boolean temp = Boolean.parseBoolean(value);<br />                  fieldSetMet.invoke(bean, temp);<br />               } else {<br />                  System.out.println("not supper type" + fieldType);<br />               }<br />            }*/<br />         _} **catch **(Exception e) {<br />            **continue**;<br />         }<br />      }

}

/*
判断是否存在某属性的 set方法
* @param __methods
* @param __fieldSetMet
* @return boolean
*/
private static boolean checkSetMet(Method[] methods, String fieldSetMet) {
for (Method met : methods) {
if (fieldSetMet.equals(met.getName())) {
return true;
}
}
return false;
}
/*
判断是否存在某属性的 get方法
* @param __methods
* @param __fieldGetMet
* @return boolean
*/
private static boolean checkGetMet(Method[] methods, String fieldGetMet) {
for (Method met : methods) {
if (fieldGetMet.equals(met.getName())) {
return true;
}
}
return false;
}

/*
拼接某属性的 get方法
* @param __fieldName
* @return String
*/
private static String parGetName(String fieldName) {
if (null == fieldName || “”.equals(fieldName)) {
return null;
}
return “get” + fieldName.substring(0, 1).toUpperCase()
+ fieldName.substring(1);
}
/*
拼接在某属性的 set方法
* @param __fieldName
* @return String
*/
private static String parSetName(String fieldName) {
if (null == fieldName || “”.equals(fieldName)) {
return null;
}
return “set” + fieldName.substring(0, 1).toUpperCase()
+ fieldName.substring(1);
}

public static void List(List list){
list.forEach(o -> {
Null2EmptyString.Perform(o);
});
}
public static void Perform(Object bean){
try {
Class<? extends Object> type = bean.getClass();
BeanInfo beanInfo = Introspector.getBeanInfo(type);

     Field[] fields = type.getDeclaredFields();<br />         Map<String,String> fieldmap = **new **HashMap<>();<br />         **for**(**int **i = 0; i < fields.**length **;i++){<br />            fieldmap.put(fields[i].getName().toLowerCase(),fields[i].getType().getSimpleName().toLowerCase());<br />         }
     PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();<br />         **for **(**int **i = 0; i < propertyDescriptors.**length**; i++) {<br />            PropertyDescriptor descriptor = propertyDescriptors[i];<br />            String propertyName = descriptor.getName();<br />            **if **(!**"class"**.equals(propertyName)) {<br />               Method readMethod = descriptor.getReadMethod();<br />               Method writeMethod = descriptor.getWriteMethod();<br />               Object result = readMethod.invoke(bean, **new **Object[0]);<br />               **if **(result != **null**) {<br />               }**else**{<br />                  **if**(writeMethod != **null**) {<br />                     **try **{<br />                        **if**(fieldmap.containsKey(propertyName.toLowerCase()) && fieldmap.get(propertyName.toLowerCase()).equals(**"string"**)) {<br />                           _//Object[] oParam = new Object[]{};<br />                           //oParam = new String[]{("")};<br />                           //注意这里的参数。<br />                           //writeMethod.invoke(bean, oParam);<br />                           _writeMethod.invoke(bean, **""**);<br />                        }<br />                     } **catch **(IllegalArgumentException iea) {<br />                        System.**_out_**.println(**"参数错误:" **+ propertyName);<br />                        iea.printStackTrace();<br />                     }<br />                  }<br />               }
        }<br />         }<br />      }<br />      **catch**(Exception e){<br />         e.printStackTrace();<br />      }<br />   }

}