OSChina底层数据库操作的类(QueryHelper)源代码

OSChina 使用的是 dbutils 这个JDBC的封装类库来进行数据库操作。

而 QueryHelper 则是在 dbutils 的基础上进行一级简单的封装，提供一些经常使用的数据库操作方法和对数据缓存的支持。

数据库连接的释放方法请看这里。

标签： OSCHINA JDBC 数据库 DbUtils

[1].[代码] QueryHelper.java 跳至 [1]

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package my.db;   import java.io.Serializable; import java.math.BigInteger; import java.sql.*; import java.util.*;   import my.cache.CacheManager; import net.oschina.Configurations;   import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.*; import org.apache.commons.lang.ArrayUtils;   /**  * 数据库查询助手  * @author Winter Lau<br> */ @SuppressWarnings("unchecked") public class QueryHelper {           private final static QueryRunner _g_runner = new QueryRunner();     private final static ColumnListHandler _g_columnListHandler = new ColumnListHandler(){         @Override         protected Object handleRow(ResultSet rs) throws SQLException {             Object obj = super.handleRow(rs);             if(obj instanceof BigInteger)                 return ((BigInteger)obj).longValue();             return obj;         }               };     private final static ScalarHandler _g_scaleHandler = new ScalarHandler(){         @Override         public Object handle(ResultSet rs) throws SQLException {             Object obj = super.handle(rs);             if(obj instanceof BigInteger)                 return ((BigInteger)obj).longValue();             return obj;         }           };           private final static List<Class<?>> PrimitiveClasses = new ArrayList<Class<?>>(){{         add(Long.class);         add(Integer.class);         add(String.class);         add(java.util.Date.class);         add(java.sql.Date.class);         add(java.sql.Timestamp.class);     }};           private final static boolean _IsPrimitive(Class<?> cls) {         return cls.isPrimitive() || PrimitiveClasses.contains(cls) ;     }           /**      * 获取数据库连接      * @return      */     public static Connection getConnection() {         try{             return Configurations.getConnection();         }catch(SQLException e){             throw new DBException(e);         }     }       /**      * 读取某个对象      * @param sql      * @param params      * @return      */     @SuppressWarnings("rawtypes")     public static <T> T read(Class<T> beanClass, String sql, Object...params) {         try{             return (T)_g_runner.query(getConnection(), sql, _IsPrimitive(beanClass)?_g_scaleHandler:new BeanHandler(beanClass), params);         }catch(SQLException e){             throw new DBException(e);         }     }           public static <T> T read_cache(Class<T> beanClass, String cache, Serializable key, String sql, Object...params) {         T obj = (T)CacheManager.get(cache, key);         if(obj == null){             obj = read(beanClass, sql, params);             CacheManager.set(cache, key, (Serializable)obj);         }         return obj;     }           /**      * 对象查询      * @param <T>      * @param beanClass      * @param sql      * @param params      * @return      */     @SuppressWarnings("rawtypes")     public static <T> List<T> query(Class<T> beanClass, String sql, Object...params) {         try{             return (List<T>)_g_runner.query(getConnection(), sql, _IsPrimitive(beanClass)?_g_columnListHandler:new BeanListHandler(beanClass), params);         }catch(SQLException e){             throw new DBException(e);         }     }       /**      * 支持缓存的对象查询      * @param <T>      * @param beanClass      * @param cache_region      * @param key      * @param sql      * @param params      * @return      */     public static <T> List<T> query_cache(Class<T> beanClass, String cache_region, Serializable key, String sql, Object...params) {               List<T> objs = (List<T>)CacheManager.get(cache_region, key);         if(objs == null){             objs = query(beanClass, sql, params);             CacheManager.set(cache_region, key, (Serializable)objs);         }         return objs;     }           /**      * 分页查询      * @param <T>      * @param beanClass      * @param sql      * @param page      * @param count      * @param params      * @return      */     public static <T> List<T> query_slice(Class<T> beanClass, String sql, int page, int count, Object...params) {         if(page < 0 || count < 0)             throw new IllegalArgumentException("Illegal parameter of 'page' or 'count', Must be positive.");         int from = (page - 1) * count;         count = (count > 0) ? count : Integer.MAX_VALUE;         return query(beanClass, sql + " LIMIT ?,?", ArrayUtils.addAll(params, new Integer[]{from,count}));          }           /**      * 支持缓存的分页查询      * @param <T>      * @param beanClass      * @param cache      * @param cache_key      * @param cache_obj_count      * @param sql      * @param page      * @param count      * @param params      * @return      */     public static <T> List<T> query_slice_cache(Class<T> beanClass, String cache, Serializable cache_key, int cache_obj_count, String sql, int page, int count, Object...params) {         List<T> objs = (List<T>)CacheManager.get(cache, cache_key);         if(objs == null) {             objs = query_slice(beanClass, sql, 1, cache_obj_count, params);             CacheManager.set(cache, cache_key, (Serializable)objs);         }         if(objs == null || objs.size()==0)             return objs;         int from = (page - 1) * count;         if(from < 0)             return null;         if((from+count) > cache_obj_count)//超出缓存的范围             return query_slice(beanClass, sql, page, count, params);         int end = Math.min(from + count, objs.size());         if(from >= end)             return null;         return objs.subList(from, end);     }           /**      * 运行统计查询语句。语句的运行结果必须仅仅返回一个数值      * @param sql      * @param params      * @return      */     public static long stat(String sql, Object...params) {         try{             Number num = (Number)_g_runner.query(getConnection(), sql, _g_scaleHandler, params);             return (num!=null)?num.longValue():-1;         }catch(SQLException e){             throw new DBException(e);         }     }       /**      * 运行统计查询语句。语句的运行结果必须仅仅返回一个数值      * @param cache_region      * @param key      * @param sql      * @param params      * @return      */     public static long stat_cache(String cache_region, Serializable key, String sql, Object...params) {         Number value = (Number)CacheManager.get(cache_region, key);         if(value == null){             value = stat(sql, params);             CacheManager.set(cache_region, key, value);         }         return value.longValue();     }       /**      * 运行INSERT/UPDATE/DELETE语句      * @param sql      * @param params      * @return      */     public static int update(String sql, Object...params) {         try{             return _g_runner.update(getConnection(), sql, params);         }catch(SQLException e){             throw new DBException(e);         }     }           /**      * 批量运行指定的SQL语句      * @param sql      * @param params      * @return      */     public static int[] batch(String sql, Object[][] params) {         try{             return _g_runner.batch(getConnection(), sql, params);         }catch(SQLException e){             throw new DBException(e);         }     } }