Java Web Dao层设计

UML设计图

Dao层设计

实体类

package cn.zzuli.oa.domain;

public class Role {

}

package cn.zzuli.oa.domain;

public class User {

private Long id;

private String username;

public User() {

super();

}

public Long getId() {

return id;

}

public void setId(Long id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

}

BaseDao接口

package cn.zzuli.oa.base;

import java.util.List;

public interface BaseDao {

/**

* 保存实体

* @param entity

*/

void save(T entity);

/**

* 删除实体

* @param id

*/

void delete(Long id);

/**

* 更新实体

* @param entity

*/

void update(T entity);

/**

*

* @param id

* @return

*/

T getById(Long id);

/**

* 查询实体

* @param ids id的集合

* @return

*/

List listByIds(Long[] ids);

/**

* 查询所有

* @return

*/

List listAll();

}

BaseDaoImpl代码，实现BaseDao接口

package cn.zzuli.oa.base.impl;

import java.lang.reflect.ParameterizedType;

import java.util.Collections;

import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import cn.zzuli.oa.base.BaseDao;

@SuppressWarnings("unchecked")

public abstract class BaseDaoImpl implements BaseDao {

@Resource

private SessionFactory sessionFactory;

protected Class clazz;

public BaseDaoImpl() {

//通过反射得到T的真实类型

ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();//获取这个父类的泛型类型

this.clazz = (Class) pt.getActualTypeArguments()[0]; //获取第一个泛型T的类型

System.out.println("clazz = " + clazz.getName());

}

@Override

public void save(T entity) {

getSession().save(entity);

}

@Override

public void delete(Long id) {

Object obj = getSession().get(clazz, id);

getSession().delete(obj);

}

@Override

public void update(T entity) {

getSession().update(entity);

}

@Override

public T getById(Long id) {

return (T) getSession().get(clazz, id);

}

@Override

public List listByIds(Long[] ids) {

if (ids == null || ids.length == 0) {

return Collections.EMPTY_LIST;

}

return getSession().createQuery("FROM " + clazz.getSimpleName() + " WHERE id IN(:ids)")

.setParameterList("ids", ids).list();

}

@Override

public List listAll() {

return getSession().createQuery("FROM " + clazz.getSimpleName()).list();

}

/**

* 获取当前可用的Session

*

* @return 当前可用的Session

*/

protected Session getSession() {

return sessionFactory.getCurrentSession();

}

}

RoleDao接口，继承BaseDao

package cn.zzuli.oa.dao;

import cn.zzuli.oa.base.BaseDao;

import cn.zzuli.oa.domain.Role;

public interface RoleDao extends BaseDao {

}

UserDao接口，继承BaseDao

UserDao实现类UserDaoImpl可以实现的自己的功能代码

package cn.zzuli.oa.dao;

import cn.zzuli.oa.base.BaseDao;

import cn.zzuli.oa.domain.User;

public interface UserDao extends BaseDao{

}

RoleDaoImpl代码，继承BaseDaoImpl，实现RoleDao

package cn.zzuli.oa.dao.impl;

import org.springframework.stereotype.Repository;

import cn.zzuli.oa.base.impl.BaseDaoImpl;

import cn.zzuli.oa.dao.RoleDao;

import cn.zzuli.oa.domain.Role;

@Repository

public class RoleDaoImpl extends BaseDaoImpl implements RoleDao {

}

UserDaoImpl代码，继承BaseDaoImpl，实现UserDao

package cn.zzuli.oa.dao.impl;

import org.springframework.stereotype.Repository;

import cn.zzuli.oa.base.impl.BaseDaoImpl;

import cn.zzuli.oa.dao.UserDao;

import cn.zzuli.oa.domain.User;

@Repository

public class UserDaoImpl extends BaseDaoImpl implements UserDao{

}

测试类

package cn.zzuli.oa.base;

import org.junit.Test;

import cn.zzuli.oa.dao.RoleDao;

import cn.zzuli.oa.dao.UserDao;

import cn.zzuli.oa.dao.impl.RoleDaoImpl;

import cn.zzuli.oa.dao.impl.UserDaoImpl;

import cn.zzuli.oa.domain.Role;

import cn.zzuli.oa.domain.User;

public class BaseDaoTest {

@Test

public void testGetById() {

UserDao userDao = new UserDaoImpl();

RoleDao roleDao = new RoleDaoImpl();

}

}

实现效果

实现效果

此处输出的正是BaseDao实现类BaseDaoImple中构造方法获取的泛型的类型，