spring mybatis 通过MapperFactoryBean整合基类Service

当我们使用spring mybatis Mapper 自动扫描接口机制，生成Dao ，Mybatis 可以映射自动生成Mapper ，和Bean,XMl 文件。Service实现类可以通过注入相应的Mapper 即可调用Mapper中的方法，但是如果在controller 层或者其他Service类引入其他Service类，想调用自动生成的Mapper方法时，需要在Service 重新封装方法，才可以调用基础Mapper 方法，这就很麻烦。所以在此，构造公用的Service 父类，所有子类继承，即可调用Mapper 原生生成的方法，从而达到在Service中控制事务，并且不用ServiceImpl 实现类，重新封装方法

BaseService 接口，接口的方法和自动生成的Mapper 相对应

package com.ancoin.offical.service.base;

import java.util.List;

import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.session.RowBounds;



public interface BaseService<T> {

	 /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    long countByExample(Object ex);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int deleteByExample(Object ex);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int deleteByPrimaryKey(Object Id);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int insert(T entity);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int insertSelective(T entity);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    List<T> selectByExampleWithRowbounds(Object ex, RowBounds rowBounds);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    List<T> selectByExample(Object ex);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    T selectByPrimaryKey(Object Id);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int updateByExampleSelective(T record, Object example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int updateByExample(T record, Object example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int updateByPrimaryKeySelective(T record);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table t_coin_info
     *
     * @mbg.generated
     */
    int updateByPrimaryKey(T entity);
}

　　BaseServiceImpl 实现类

package com.ancoin.offical.service.base.impl;

import java.lang.reflect.ParameterizedType;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.mapper.MapperFactoryBean;
import org.springframework.util.StringUtils;

import com.ancoin.offical.config.SpringContextAware;
import com.ancoin.offical.service.base.BaseService;
/**
 * 
 * @author LZH 2018-02-24
 *
 * @param <T>
 */
public abstract  class BaseServiceImpl<T> implements BaseService<T>{
	
	private Class<T> entityclass;
	private String NameSpace;
    private SqlSession sqlSession;

	public BaseServiceImpl() {
		
		entityclass =(Class<T>)((ParameterizedType)this.getClass().getGenericSuperclass()).getActualTypeArguments()[0];
		try {
			
			NameSpace = "com.ancoin.offical.dao.def."+entityclass.getSimpleName()+"Mapper.";
			String beanName = StringUtils.uncapitalize(entityclass.getSimpleName()+"MapperEx");
			System.out.println(beanName);
			MapperFactoryBean	mapperFactoryBean = SpringContextAware.getBean("&"+beanName);
			sqlSession = mapperFactoryBean.getSqlSession();
			
		} catch (Exception e) {
			
			e.printStackTrace();
		}
	
	}
	
	
	@Override
	public long countByExample(Object ex) {
		Object obj = sqlSession.selectOne(NameSpace+"countByExample", ex);
		
		if(obj==null)return 0;
		else {
			return (long) obj;
		}
	}

	@Override
	public int deleteByExample(Object ex) {
		return sqlSession.delete(NameSpace+"deleteByExample", ex);
		
	}

	@Override
	public int deleteByPrimaryKey(Object Id) {
		return sqlSession.delete(NameSpace+"deleteByPrimaryKey", Id);
	}

	@Override
	public int insert(Object entity) {
		
		return sqlSession.insert(NameSpace+"insert", entity);
	}

	@Override
	public int insertSelective(Object entity) {
		return sqlSession.insert(NameSpace+"insertSelective", entity);
	}

	@Override
	public List selectByExampleWithRowbounds(Object ex, RowBounds rowBounds) {
		
		return sqlSession.selectList(NameSpace+"selectByExampleWithRowbounds", ex, rowBounds);
	}

	@Override
	public List<T> selectByExample(Object ex) {
		
		return sqlSession.selectList(NameSpace+"selectByExample", ex);
	}

	@Override
	public T selectByPrimaryKey(Object Id) {
		
		return sqlSession.selectOne(NameSpace+"selectByPrimaryKey",Id);
	}

	@Override
	public int updateByExampleSelective(Object record, Object example) {
		Map params = new HashMap();
		params.put("record", record);
		params.put("example", example);
		return sqlSession.update(NameSpace+"updateByExampleSelective", params);
	}

	@Override
	public int updateByExample(Object record, Object example) {
		Map params = new HashMap();
		params.put("record", record);
		params.put("example", example);
		return sqlSession.update(NameSpace+"updateByExample", params);
	}

	@Override
	public int updateByPrimaryKeySelective(Object record) {
		
		return sqlSession.update(NameSpace+"updateByPrimaryKeySelective", record);
	}

	@Override
	public int updateByPrimaryKey(Object entity) {
		
		return sqlSession.update(NameSpace+"updateByPrimaryKey", entity);
	}

	
}

　　这里的NameSpace 是相应类下面的xml 文件配置的NameSpace ,配置不一样，这里的值不一样，哟有一定的规律。beanName这里表示MapperFactoryBean 给每个Mapper生成的动态代理实现，Mapper 在扫描实例化时，会给每个Mapper生成一个MapperFactoryBean 代理实现类，如果不知道，可以 改一下 ，改成MapperFactoryBean mapperFactoryBean = SpringContextAware.getBean(MapperFactoryBean .class); 让它报错，就可以知道当前有多少个Mapper 代理实现类。

我这里在前面加“&”是因为报错时有带&。上面写法注意是为了拿到当前的sqlSession，只要拿到sqlSession 下面一切都好办