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  • MyBatis使用(一)

    特殊封装dao方法:

    public class MyBatisDAO extends SqlSessionDaoSupport {
    
    	private static final Logger logger = LoggerFactory.getLogger("SQL_LOGGER");
    
    	public MyBatisDAO() {}
    
    	/**
    	 * 插入一个实体
    	 * @param sqlMapId mybatis 映射id
    	 * @param object 实体参数
    	 * @return
    	 */
    	public int insert(final String sqlMapId, final Object object) {
    
    		return (Integer) execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    				try{
    					return session.insert(sqlMapId, object);
    				}catch(Exception e){
                        e.printStackTrace();
    					 logger.info("sql:{}",sqlMapId);
    					 logger.error("fail to execute the sql",e);					 
    					 throw new RuntimeException("数据库操作异常"+e.getMessage());
    				}
    			}
    		});
    	}
    
    	/**
    	 * 查询列表
    	 * @param sqlMapId mybatis映射id
    	 * @return
    	 */
    	@SuppressWarnings("rawtypes")
    	public List findForList(String sqlMapId) {
    		return findForList(sqlMapId, null);
    	}
    
    	/**
    	 * 查询列表
    	 * @param sqlMapId mybatis映射id
    	 * @param param 查询参数
    	 * @return
    	 */
    	@SuppressWarnings("rawtypes")
    	public List findForList(final String sqlMapId, final Object param) {
    
    		return (List) execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    				try{
    					if (param != null) {
    						return session.selectList(sqlMapId, param);
    					} else {
    						return session.selectList(sqlMapId);
    					}
    				}catch(Exception e){
                        e.printStackTrace();
    					 logger.info("sql:{}",sqlMapId);
    					 logger.error("fail to execute the sql",e);
                        throw new RuntimeException("数据库操作异常"+e.getMessage());
    				}
    			}
    		});
    	}
    
    	/**
    	 * 查询列表
    	 * @param sqlMapId mybatis映射id
    	 * @param param 查询参数
    	 * @param offset 查询起始位置(偏移量),从1开始
    	 * @param limit 查询数量,必须大于0
    	 * @return
    	 */
    	@SuppressWarnings("rawtypes")
    	public List findForList(final String sqlMapId, final Object param,
    			final int offset, final int limit) {
    
    		return (List) execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    				try{
    					return session.selectList(sqlMapId, param, new RowBounds(offset, limit));
    				}catch(Exception e){
                        e.printStackTrace();
    					logger.info("sql:{}",sqlMapId);
    					logger.error("fail to execute the sql",e);
                        throw new RuntimeException("数据库操作异常"+e.getMessage());
    				}
    			}
    		});
    	}
    
    	/**
    	 * 获取结果集的map
    	 * @param sqlMapId mybatis映射id
    	 * @param mapMapper 处理多行结果集的接口,指定map的key和value
    	 * @return 结果对象的map
    	 */
    	@SuppressWarnings("rawtypes")
    	public Map findForMap(final String sqlMapId, final MapMapper mapMapper) {
    		return findForMap(sqlMapId, null, mapMapper);
    	}
    
    	/**
    	 * 获取结果集的map
    	 * @param sqlMapId mybatis映射id
    	 * @param parameter 参数数组
    	 * @param mapMapper 处理多行结果集的接口,指定map的key和value
    	 * @return
    	 */
    	@SuppressWarnings({ "rawtypes", "unchecked" })
    	public Map findForMap(final String sqlMapId, final Object parameter,
    			final MapMapper mapMapper) {
    
    		List list = null;
    		if (parameter == null) {
    			list = findForList(sqlMapId);
    		} else {
    			list = findForList(sqlMapId, parameter);
    		}
    
    		Map result = new HashMap();
    		for (int i = 0; i < list.size(); i++) {
    			result.put(mapMapper.mapKey(list.get(i), i + 1), mapMapper.mapValue(list.get(i), i + 1));
    		}
    		return result;
    	}
    
    	/**
    	 * 带有分页信息的查询
    	 * @param sqlMapId mybatis映射id
    	 * @param pageRequest 分页请求参数信息
    	 * @return
    	 */
    	@SuppressWarnings({ "rawtypes", "unchecked" })
    	public Page findForPage(String sqlMapId, PageRequest pageRequest) {
    
    		// 查询总数
    		pageRequest.getFilters().put(SelectCountSqlInterceptor.COUNT, null); // 设置是否需要将sql转换成总数查询sql
    		Number totalCount = (Number) findForObject(sqlMapId, pageRequest
    				.getFilters());
    		if (totalCount == null || totalCount.intValue() <= 0) {
    			return new Page(pageRequest, 0);
    		}
    		if(totalCount != null && totalCount.intValue() <= (pageRequest.getPageNumber()-1) * pageRequest.getPageSize()){
    			return new Page(pageRequest.getPageNumber(), pageRequest.getPageSize(), totalCount.intValue(), new ArrayList(0));
    		}
    		pageRequest.getFilters().remove(SelectCountSqlInterceptor.COUNT);
    
    		Map filters = new HashMap();
    		filters.putAll(pageRequest.getFilters());
    		Page page = new Page(pageRequest, totalCount.intValue());
    		List list = findForList(sqlMapId, filters, page.getFirstResult(), page.getPageSize());
    
    		page.setResult(list);
    
    		return page;
    	}
    
    	/**
    	 * 查询得到一个实体
    	 * @param sqlMapId mybatis映射id
    	 * @return
    	 */
    	public Object findForObject(final String sqlMapId) {
    
    		return findForObject(sqlMapId, null);
    	}
    
    	/**
    	 * 查询得到一个实体
    	 * @param sqlMapId mybatis映射id
    	 * @param param 查询参数
    	 * @return
    	 */
    	public Object findForObject(final String sqlMapId, final Object param) {
    
    		return execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    				try{
    					if (param != null) {
    						return session.selectOne(sqlMapId, param);
    					} else {
    						return session.selectOne(sqlMapId);
    					}
    				}catch(Exception e){
                        e.printStackTrace();
    					logger.info("sql:{}",sqlMapId);
    					logger.error("fail to execute the sql",e);
                        throw new RuntimeException("数据库操作异常"+e.getMessage());
    				}
    			}
    		});
    	}
    
    	/**
    	 * 修改
    	 * 
    	 * @param sqlMapId mybatis映射id
    	 * @param param 参数
    	 * @return
    	 */
    	public int update(final String sqlMapId, final Object param) {
    
    		return (Integer) execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    				try {
    					return session.update(sqlMapId, param);
    				} catch (Exception e) {
                        e.printStackTrace();
    					 logger.info("sql:{}",sqlMapId);
    					 logger.error("fail to execute the sql",e);
                        throw new RuntimeException("数据库操作异常"+e.getMessage());
    				}				
    			}
    		});
    	}
    
    	/**
    	 * 删除
    	 * @param sqlMapId mybatis映射id
    	 * @return
    	 */
    	public int delete(final String sqlMapId) {
    
    		return delete(sqlMapId, null);
    	}
    
    	/**
    	 * 带有参数删除
    	 * @param sqlMapId mybatis映射id
    	 * @param param 参数
    	 * @return
    	 */
    	public int delete(final String sqlMapId, final Object param) {
    
    		return (Integer) execute(new SqlSessionCallback() {
    
    			public Object doInSession(SqlSession session) {
    
    				if (param != null) {
    					return session.delete(sqlMapId, param);
    				} else {
    					return session.delete(sqlMapId);
    				}
    			}
    		});
    	}
    
    	/**
    	 * 允许回调,暴露SqlSession给调用者
    	 * @param action
    	 * @return
    	 */
    	public Object execute(SqlSessionCallback action) {
    
    		try {
    			return action.doInSession(getSqlSession());
    		} catch (Exception e) {
                e.printStackTrace();
    			 logger.error("fail to execute the sql",e);
                throw new RuntimeException("数据库操作异常"+e.getMessage());
    		}
    	}
    
    	public interface SqlSessionCallback {
    
    		public Object doInSession(SqlSession session);
    	}
    }
    

      

    SqlSession为mybatis内置对象,用于调用配置好的mapper.xml中的sql语句

    单实例类,所有方法只调用一个SqlSession

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  • 原文地址:https://www.cnblogs.com/binbang/p/4772650.html
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