通过反射转换java数据类型

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/StriverFeng/article/details/71405639

最近项目中遇到通过类似hibernate又不是hibernate查询出来的数据是一个List<Object[]>类型,不是自己想要的key,value类型,然后抽空写了一个工具类,貌似这样破坏了java的封装性,标记一下,有不对的地方欢迎指出来

实体类:  

public class User1 {
	
	private int  id;
	
	private int age;
	
	private String name;
	
	private String sex;
	
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

	@Override
	public String toString() {
		return "User1 [id=" + id + ", age=" + age + ", name=" + name + ", sex=" + sex + "]";
	}
}

工具类 SQLToEntityUtils

public class SQLToEntityUtils{
	
	/**
	 * @方法名称: getListFromList
	 *  @功能描述: 从 List<Object[]> 转换为 List<T>
	 *  @参数 ：@param oldLst
	 *  @参数 ：@param clazz
	 *  @参数 ：@return
	 *  @返回类型：List<T>
	 *  @创建时间 ：2017年5月8日上午11:55:14
	 */
	public static   <T> List<T>   getListFromList(List<Object[]> oldLst,Class<T> clazz){
		if (null == clazz || null == oldLst || oldLst.isEmpty() ) {
			return null;
		}
		List<T> newLst=new ArrayList<T>();
		try {
			Field[] fields = clazz.getDeclaredFields();
			if (null == fields) {
				return null;
			}
			for (int i=0 ; i<oldLst.size(); i++) {
				Object[] obj = oldLst.get(i);
				//实体类对象
				T newObj = clazz.newInstance();
				//遍历赋值
				for (int j = 0; j < obj.length; j++) {
					if (null !=obj[j]) {
						fields[j].setAccessible(true);
						fields[j].set(newObj, obj[j]);
					}
				}
				newLst.add(newObj);
			}
			return newLst;
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		}
		return null;
	}
	public static <T> T  getObjectFromList(List<Object[]> oldLst,Class<T> clazz){
		if (null == clazz || null == oldLst || oldLst.isEmpty() ) {
			return null;
		}
		//获取到实体类对象
		T newObj =null;
		try {
			newObj = clazz.newInstance();
			Field[] fields = clazz.getDeclaredFields();
			if (null == fields) {
				return null;
			}
				Object[] obj = oldLst.get(0);
				//遍历赋值
				for (int j = 0; j < obj.length; j++) {
					if (null !=obj[j]) {
						fields[j].setAccessible(true);
						fields[j].set(newObj, obj[j]);
					}
				}
				return newObj;
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	
	
	public static void main(String[] args) {
		Object[] obj1=new Object[]{1,13,"zhangsan","男"};
		Object[] obj2=new Object[]{1,13,"list","男"};
		Object[] obj3=new Object[]{1,13,"王五","男"};
		List<Object[]> list=new ArrayList<>();
		list.add(obj1);
		list.add(obj2);
		list.add(obj3);
//		List<User1> userList = getListFromList(list, User1.class);
		User1 user2 = getObjectFromList(list, User1.class);
		System.out.println(user2.toString());
		System.out.println();
//		for (User1 user1 : userList) {
//			System.out.println(user1.toString());
//		}
		
		
		
//		User1 user1 = getObjectFromList(list, User1.class);
//		Method[] methods = User1.class.getMethods();
//		for (Method method : methods) {
//			System.out.println(method.getName());
//		}
		Field[] fields = User1.class.getDeclaredFields();
		
//		boolean flag=int instanceof(Integer);
//		Field.setAccessible(fields, true);
		for (int i = 0; i < fields.length; i++) {
//				System.out.println(fields[i].getName());
			
		}
	}
}