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package com.dao; import java.lang.reflect.Modifier; import java.sql.Connection; import java.sql.SQLException; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.sql.DataSource; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import zuojie.esql.ESQL; public class DaoManager { public final static int READ_COMMITTED = Connection.TRANSACTION_READ_COMMITTED; public final static int SERIALIZABLE = Connection.TRANSACTION_SERIALIZABLE; private static Log log = LogFactory.getLog(DaoManager.class); private static Map<String, DaoManager> managers = new HashMap<String, DaoManager>(); public static DaoManager getInstance(String name) { return managers.get(name); } public static DaoManager getInstance() { return managers.get("default"); } public static void initialize(DataSource source) throws Exception { // 本地默认数据源 DaoManager manager = new DaoManager(); manager.setDaoPackageName("com.dao"); manager.setDatabase(Class.forName("com.dao.PostgreSQL")); manager.setDataSource(source); manager.startup(); managers.put("default", manager); } //==================================================================== private String name; private String daoPackageName; private Class<?> database; // Dao对象应该实现的类, 用于区别调入用于不同数据库的Dao private DataSource dataSource; private ESQL esql; public DaoManager() { } private Map<Class<?>, Object> daos = new HashMap<Class<?>, Object>(); /** 通过连接池数据源初始化 */ public void startup() throws Exception { managers.put(name, this); log.info("启动DAO管理器"); // 声明一个ESQL对象 esql = new ESQL(dataSource); // 设置数据存取对象 JavaPackageExplorer explorer = new JavaPackageExplorer(daoPackageName); List<String> list = explorer.explore(); for (String s : list) { log.info(s); register(s); } } /** 注册一个DAO对象 */ private void register(String name) { try { Class<?> type = Class.forName(name); if (type.equals(BaseDao.class)) return; if (!BaseDao.class.isAssignableFrom(type)) return; if (!database.isAssignableFrom(type)) return; //排除抽象类 if (Modifier.isAbstract(type.getModifiers())) return ; log.info("注册DAO类: " + name); BaseDao dao = (BaseDao) type.newInstance(); dao.setEsql(esql); Class<?>[] cs = type.getInterfaces(); for (Class<?> c : cs) { daos.put(c, dao); } } catch (Exception e) { log.error("注册DAO类失败: " + name, e); } } public <T> T getDao(Class<T> type) { Object dao = daos.get(type); if (dao == null) throw new RuntimeException("指定的DAO不存在: " + type.getCanonicalName()); return type.cast(dao); } public ESQL getEsql() { return esql; } /** 开始事务 */ public void begin(int isolation) throws Exception { try { esql.startTransaction(isolation); } catch (Exception e) { throw new Exception("开始事务错误", e); } } public void begin() throws Exception { begin(DaoManager.READ_COMMITTED); } /** 提交当前事务 */ public void commit() throws Exception { try { esql.commitTransaction(); } catch (Exception e) { throw new Exception("提交事务错误", e); } } /** 结束当前事务。如果没有提交，就回滚 */ public void end() { try { esql.endTransaction(); } catch (Exception e) { } } public void setTransactionIsolation(int isolation) throws Exception { try { esql.setTransactionIsolation(isolation); } catch (SQLException e) { throw new Exception("设置事务隔离度错误", e); } } public void setDaoPackageName(String daoPackageName) { this.daoPackageName = daoPackageName; } public void setDatabase(Class<?> database) { this.database = database; } public void setDataSource(DataSource dataSource) { this.dataSource = dataSource; } public String getName() { return name; } public void setName(String name) { this.name = name; } }