Java版的对象关系映射实现

在前面的几篇文章中,实现了获得基本类型的默认值,基本数据类型的转换等,主要的目标就是实现一个Java版的对象关系映射程序.

思路如下:

1: 对象必须是一个Java Bean.

2: 遍历对象的所有以set开头且只有一个参数的函数,为该函数提供数据值以填充该对象.

3: 如果获得的set参数值为null,则根据参数类型,以默认值对位参数调用该函数.

我的这个ORM接口名称为HiCBO,名称来自于一个C#开源项目DNN中的一个ORM转换为(CBO).

接口如下:

/**
     * 根据回调填充对象
     * @param obj
     * @param type
     * @param handler
     * @return
     */
    public static <T> boolean FillObject(T obj, Class<T> type, IEventRet8Param<String, String> handler) ;
 /**
     * 根据回调填充对象
     * @param obj
     * @param type
     * @param handler
     * @return
     */
    public static <T> boolean FillObjectEx(T obj, Class<T> type, IEventRet8Param<Object, String> handler) 

　　该接口的调用如下:

	@Test
	public void Test_CBO() {
		TestObj obj = new TestObj();
		boolean ret = HiCBO.FillObject(obj, TestObj.class, new IEventRet8Param<String, String>(){

			@Override
			public String OnEvent(String v) {
				if (v.equals("X")) {
					return "test";
				}
				if (v.equals("Y")) {
					return "3";
				}
				if (v.equals("Z")) { 
					return "2.7";
				}
				if (v.equals("Date")) {
					return "2016-05-19";
				}
				if (v.equals("Date2")) {
					return "2016-05-19";
				}
				if (v.equals("Date3")) {
					return "2016-05-19 14:03:14";
				}
				if (v.equals("Date4")) {
					return "2016-05-19 02:03:14";
				}
				return null;
			}
			
		});
		Assert.assertTrue(ret);
		Assert.assertEquals(obj.getX(), "test");
		Assert.assertEquals(obj.getY(), 3);
		Assert.assertEquals(obj.getY2(), -1);
		Assert.assertTrue(obj.getZ() == 2.7f);
		Assert.assertEquals(obj.getDate(), HiTypeHelper.Convert2Date("2016-05-19"));
		Assert.assertEquals(obj.getDate2(), HiTypeHelper.Convert2SqlDate("2016-05-19"));
		Assert.assertEquals(obj.getDate3(), HiTypeHelper.Convert2Date("2016-05-19 14:03:14"));
		Assert.assertEquals(obj.getDate4(), HiTypeHelper.Convert2SqlDate("2016-05-19 02:03:14"));
		Assert.assertEquals(obj.getDate5(), null);
	}

	@Test
	public void Test_CBOEx() {
		TestObj obj = new TestObj();
		boolean ret = HiCBO.FillObjectEx(obj, TestObj.class, new IEventRet8Param<Object, String>(){

			@Override
			public Object OnEvent(String v) {
				if (v.equals("X")) {
					return "test";
				}
				if (v.equals("Y")) {
					return 3;
				}
				if (v.equals("Z")) { 
					return 2.7;
				}
				if (v.equals("Date")) {
					return "2016-05-19";
				}
				if (v.equals("Date2")) {
					return "2016-05-19";
				}
				if (v.equals("Date3")) {
					return "2016-05-19 14:03:14";
				}
				if (v.equals("Date4")) {
					return "2016-05-19 02:03:14";
				}
				return null;
			}
			
		});
		Assert.assertTrue(ret);
		Assert.assertEquals(obj.getX(), "test");
		Assert.assertEquals(obj.getY(), 3);
		Assert.assertEquals(obj.getY2(), -1);
		Assert.assertTrue(obj.getZ() == 2.7f);
		Assert.assertEquals(obj.getDate(), HiTypeHelper.Convert2Date("2016-05-19"));
		Assert.assertEquals(obj.getDate2(), HiTypeHelper.Convert2SqlDate("2016-05-19"));
		Assert.assertEquals(obj.getDate3(), HiTypeHelper.Convert2Date("2016-05-19 14:03:14"));
		Assert.assertEquals(obj.getDate4(), HiTypeHelper.Convert2SqlDate("2016-05-19 02:03:14"));
		Assert.assertEquals(obj.getDate5(), null);
	}

　　

package HiJUtil.Test;

public class TestObj {
	public String x;
	public String getX() {
		return x;
	}
	public void setX(String x) {
		this.x = x;
	}
	public int getY() {
		return y;
	}
	public void setY(int y) {
		this.y = y;
	}
	public float getZ() {
		return z;
	}
	public void setZ(float z) {
		this.z = z;
	}
	public int y;
	public float z;
	
	private java.util.Date date;
	public java.util.Date getDate() {
		return date;
	}
	public void setDate(java.util.Date date) {
		this.date = date;
	}	

	private java.sql.Date date2;
	public java.sql.Date getDate2() {
		return date2;
	}
	public void setDate2(java.sql.Date date2) {
		this.date2 = date2;
	}
	private java.util.Date date3;
	public java.util.Date getDate3() {
		return date3;
	}
	public void setDate3(java.util.Date date3) {
		this.date3 = date3;
	}
	private java.sql.Date date4;
	public java.sql.Date getDate4() {
		return date4;
	}
	public void setDate4(java.sql.Date date4) {
		this.date4 = date4;
	}
	
	public int y2;
	public int getY2() {
		return y2;
	}
	public void setY2(int y2) {
		this.y2 = y2;
	}
	private java.util.Date date5;
	public java.util.Date getDate5() {
		return date5;
	}
	public void setDate5(java.util.Date date5) {
		this.date5 = date5;
	}
}

　　该接口实现代码如下:

    /**
     * 根据提供数据装载对象
     * @param obj
     * @param type
     * @param handler
     * @return
     */
    private static <T> boolean FillObject(T obj, Class<T> type, IEventRet8Param2<Object, Class<?>, String> handler)   {
    	if (obj == null || handler == null) {
    		return false;
    	}
    	
    	Method[] methods = type.getMethods();
    	
    	for (int i = 0; i < methods.length; i++) {
    		Method method = methods[i];
    		String name = method.getName();
    		if (!name.startsWith("set")) {
    			continue;
    		}
    		
    		if (method.getParameters().length != 1) {
    			continue;
    		}
    		
    		Class<?> cls = method.getParameterTypes()[0];
    		if (cls == null) {
    			continue;
    		}
    		String property = name.substring(3, name.length());
    		
    		try {     
        		Object value = handler.OnEvent(cls, property);  
    			Object ret =  HiTypeHelper.Cast(cls, value);
				method.invoke(obj, ret); 			
    		} catch(Exception ex) {
    			ex.printStackTrace();
    		}
    	}
        return true;
    }

　　

/**
     * 根据回调填充对象
     * @param obj
     * @param type
     * @param handler
     * @return
     */
    public static <T> boolean FillObject(T obj, Class<T> type, IEventRet8Param<String, String> handler)  {
    	return FillObject(obj, type, new IEventRet8Param2<Object, Class<?>, String>(){
    		public Object OnEvent(Class<?> cls, String property) {
    			return handler.OnEvent(property);
    		}
    	});
    }

	
    /**
     * 根据回调填充对象
     * @param obj
     * @param type
     * @param handler
     * @return
     */
    public static <T> boolean FillObjectEx(T obj, Class<T> type, IEventRet8Param<Object, String> handler)   {
    	return FillObject(obj, type, new IEventRet8Param2<Object, Class<?>, String>(){
    		public Object OnEvent(Class<?> cls, String property) {
    			return handler.OnEvent(property);
    		}
    	});
    }