java基础类型转换

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;

public class BeanUtil {
    
    public static String toString(Object obj){
        return obj==null?null:obj.toString();
    }
    
    public static Integer toInteger(Object obj){
        return obj==null?null:Integer.parseInt(obj.toString());
    }
    
    public static Long toLong(Object obj){
        return obj==null?null:Long.parseLong(obj.toString());
    }
    
    public static Double toDouble(Object obj) {
        return obj==null?null:Double.parseDouble(obj.toString());
    }
    
    public static Date toDate(Object obj){
        try {
            if(obj!=null){
                SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
                return sdf.parse(sdf.format(obj));
            }
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
    
    
    public static List toList(Object obj,String separator){
        String str=toString(obj);
        if(str==null){
            return new ArrayList();
        }
        return Arrays.asList(StringUtils.split(str, separator));
    }

    /**
     * 将一个 JavaBean 对象转化为一个  Map
     * @param bean 要转化的JavaBean 对象
     * @return 转化出来的  Map 对象
     * @throws IntrospectionException 如果分析类属性失败
     * @throws IllegalAccessException 如果实例化 JavaBean 失败
     * @throws InvocationTargetException 如果调用属性的 setter 方法失败
     */
    
    public static Map convertBean(Object bean){
        Map returnMap = new HashMap();
        
        try {
            BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
            PropertyDescriptor[] propertyDescriptors =  beanInfo.getPropertyDescriptors();
            for (int i = 0; i< propertyDescriptors.length; i++) {
                PropertyDescriptor descriptor = propertyDescriptors[i];
                String propertyName = descriptor.getName();
                if (!propertyName.equals("class")) {
                    Method readMethod = descriptor.getReadMethod();
                    Object result = readMethod.invoke(bean, new Object[0]);
                    if (result != null) {
                        returnMap.put(propertyName, result);
                    } else {
                        returnMap.put(propertyName, "");
                    }
                }
            }
        } catch (IntrospectionException e) {
            e.printStackTrace();//如果分析类属性失败
        } catch (IllegalAccessException e) {
            e.printStackTrace();//如果实例化 JavaBean 失败
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();//如果调用属性的 setter 方法失败
        }

        return returnMap;
    }
    
    /**
     * 将一个 Map 对象转化为一个 JavaBean
     * @param 
     * @param type 要转化的类型
     * @param map 包含属性值的 map
     * @return 转化出来的 JavaBean 对象
     */
    public static  T convertMap(Class type, Map map) {
        try {
            BeanInfo beanInfo= Introspector.getBeanInfo(type);// 获取类属性
            T obj = type.newInstance(); // 创建 JavaBean 对象
            
            // 给 JavaBean 对象的属性赋值
            PropertyDescriptor[] propertyDescriptors =  beanInfo.getPropertyDescriptors();
            for (int i = 0; i< propertyDescriptors.length; i++) {
                PropertyDescriptor descriptor = propertyDescriptors[i];
                String propertyName = propertyDescriptors[i].getName();
                if (map.containsKey(propertyName)) {
                    descriptor.getWriteMethod().invoke(obj, map.get(propertyName));
                }
            }
            
            return obj;
        } catch (IntrospectionException e) {
            e.printStackTrace();//如果分析类属性失败
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } 
        return null;
    }
    
}