试着写了个MyBatis的GenericDao

最新推荐文章于 2023-05-30 15:14:55 发布

最新推荐文章于 2023-05-30 15:14:55 发布 · 253 阅读

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本文介绍了一个使用Java和MyBatis实现的泛型DAO接口及其具体实现细节，该实现支持基本的CRUD操作，包括查询所有记录、添加记录、删除记录、根据ID查找记录和更新记录。

Interface：

package com.xlaohe1.example.dao;

import java.io.Serializable;
import java.util.List;

public interface GenericDao<T, PK extends Serializable> {

	public List<T> findAll();

	public void add(T t);

	public void delete(PK id);

	public T findById(PK id);

	public void update(T t);

}

Implments：


package com.xlaohe1.example.dao.impl;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.util.List;

import org.apache.ibatis.session.SqlSession;

import com.xlaohe1.example.dao.GenericDao;
import com.xlaohe1.example.util.Util;

public class GenericDaoImpl<T, PK extends Serializable> implements GenericDao<T, PK> {
	/*private static SqlSession session;
	static {
		session = Util.getSqlSessionFactory().openSession();
	}*/
	Class<T> clazz;
	@SuppressWarnings("unchecked")
	public GenericDaoImpl() {
		clazz = (Class<T>)((ParameterizedType)getClass().getGenericSuperclass()).getActualTypeArguments()[0];
	}
	@SuppressWarnings("unchecked")
	public List<T> findAll() {
		SqlSession session = Util.getSqlSessionFactory().openSession();
		List<T> lists = null;
		try {
			StringBuffer sb = new StringBuffer(clazz.getName());
			sb.append("Mapper").append(".find");
			lists = session.selectList(sb.toString());
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			session.close();
		}
		return lists;
	}

	public void add(T t) {
		SqlSession session = Util.getSqlSessionFactory().openSession();
		try {
			StringBuffer sb = new StringBuffer(clazz.getName());
			sb.append("Mapper").append(".insertOne");
			session.insert(sb.toString(), t);
			session.commit();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			session.close();
		}
	}


	public void delete(PK id) {
		SqlSession session = Util.getSqlSessionFactory().openSession();
		try {
			StringBuffer sb = new StringBuffer(clazz.getName());
			sb.append("Mapper").append(".del");
			session.insert(sb.toString(), id);
			session.commit();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			session.close();
		}
	}


	@SuppressWarnings("unchecked")
	public T findById(PK id) {
		SqlSession session = Util.getSqlSessionFactory().openSession();
		T t = null;
		try {
			StringBuffer sb = new StringBuffer(clazz.getName());
			sb.append("Mapper").append(".selectOne");
			t = (T)session.selectOne(sb.toString(), id);
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			session.close();
		}
		return t;
	}

	public void update(T t) {
		SqlSession session = Util.getSqlSessionFactory().openSession();
		try {
			StringBuffer sb = new StringBuffer(clazz.getName());
			sb.append("Mapper").append(".update");
			session.update(sb.toString(), t);
			session.commit();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			session.close();
		}
	}


}