Java5泛型的T_class的获取

参照ThreadLocal<T>完成如下

public abstract class BaseHelper<T> {
    private T object = null;
    private HttpServletRequest request;
    private String key;


    public BaseHelper(HttpServletRequest request, String key) {
        this.request = request;
        this.key = key;

        object = (T)request.getSession().getAttribute(key);
        if(object == null){
            object = initValue();
        }
    }

    public T get(){
        return object;
    }

    protected abstract T initValue();
}

public class BaseHelperTest extends TestCase {
    private BaseHelper<Product> sm;

    protected void setUp() throws Exception {
        HttpServletRequest request = new MockHttpServletRequest();

        sm = new BaseHelper<Product>(request, "x_key"){
            protected Product initValue(){
                return new Product();
            }
        };
    }

    protected void tearDown() throws Exception {
        super.tearDown();
    }

    /*
     * Test method for 'com.ecc.beauty.common.page.SessionManager.getAttrbute(String)'
     */
    public void testGet() {
        assertNotNull(sm.get());
    }

}

public abstract class BaseHelper<T> {
	private T object = null;
	private HttpServletRequest request;
	private String key;


	public BaseHelper(HttpServletRequest request, String key) {
		this.request = request;
		this.key = key;
		
		object = (T)request.getSession().getAttribute(key);
		if(object == null){
			object = initValue();
		}
	}
	
	public T get(){
		return object;
	}
	
	protected abstract T initValue();
}

public class BaseHelperTest extends TestCase {
	private BaseHelper<Product> sm;
	
	protected void setUp() throws Exception {
		HttpServletRequest request = new MockHttpServletRequest();
		
		sm = new BaseHelper<Product>(request, "x_key"){
			protected Product initValue(){
				return new Product();
			}
		};
	}

	protected void tearDown() throws Exception {
		super.tearDown();
	}

	/*
	 * Test method for 'com.ecc.beauty.common.page.SessionManager.getAttrbute(String)'
	 */
	public void testGet() {
		assertNotNull(sm.get());
	}

}

这种方式可以实现一个类代替 A B C等一系列类，但是在每一个用到的地方都写这样一段代码感觉不够优雅

Java代码

sm = new BaseHelper<Product>(request, "x_key"){
            protected Product initValue(){
                return new Product();
            }
        };

方法B：Class<T> entityClass = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];