JAva反射getterとsetter

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class GetterSetter {

	/**
	 * java bean get 
	 * 
	 * @param claz
	 * @param fieldName 
	 * @return
	 */
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public Method getGetter(Class claz, String fieldName) {
		StringBuilder sb = new StringBuilder();
		sb.append("get").append(fieldName.substring(0, 1).toUpperCase())
				.append(fieldName.substring(1));
		try {
			Class[] types = new Class[] {};
			return claz.getMethod(sb.toString(), types);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * java bean set 
	 * 
	 * @param claz
	 * @param fieldName 
	 * @return
	 */
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public static Method getSetter(Class claz, String fieldName) {
		try {
			Class[] parameterTypes = new Class[1];
			Field field = claz.getDeclaredField(fieldName);
			parameterTypes[0] = field.getType();//  
			StringBuilder sb = new StringBuilder();
			sb.append("set").append(fieldName.substring(0, 1).toUpperCase())
					.append(fieldName.substring(1));
			Method method = claz.getMethod(sb.toString(), parameterTypes);
			return method;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 *  set 
	 * 
	 * @param t 
	 * @param fieldName 
	 * @param value 
	 */

	public void invokeSetter(T t, String fieldName, Object value) {
		Method method = getSetter(t.getClass(), fieldName);
		try {
			method.invoke(t, new Object[] { value });
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 *  get 
	 * 
	 * @param t 
	 * @param fieldName 
	 */
	public Object invokeGetter(T t, String fieldName) {
		Method method = getGetter(t.getClass(), fieldName);
		try {
			return method.invoke(t, new Object[0]);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		GetterSetter gs = new GetterSetter();
		User user = new User();
		for (int i = 0; i < 33; i++) {
			gs.invokeSetter(user, "id", 1);
			System.out.println(gs.invokeGetter(user, "id"));
		}
	}

}