java JDBC之BasicDao--Java笔记
2022/1/19 17:50:58
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目录
BasicDao
相关的类
BasicDao
①.专门和数据交互(对数据库进行CRUD操作)
②.一张表对应一个 Dao
③.JavaBean == domain == pojo
BasicDao bd = new BasicDao<cc>(); String sql = "select * from cc"; List<cc> i = bd.DaoList(sql, cc.class); for (cc cc : i) { System.out.println(cc); } sql = "update cc set num = 22 where id = 1"; bd.update(sql); sql = "select * from cc where id =?"; System.out.println(); System.out.println(bd.DaoSingeList(sql, cc.class, 1)); sql = "select nname from cc where num =?"; System.out.println(); System.out.println(bd.DaoSinge(sql, 22));
输出:
id=1, nname=a, num=20
id=3, nname=c, num=0
id=4, nname=d, num=100
id=5, nname=e, num=666
id=2, nname=b, num=-10
id=6, nname=f, num=1id=1, nname=a, num=22
a
相关的类
import java.sql.Connection; import java.util.List; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import org.apache.commons.dbutils.handlers.BeanListHandler; import org.apache.commons.dbutils.handlers.ScalarHandler; public class BasicDao<T> { private QueryRunner qr = new QueryRunner(); // 增删改 public int update(String sql, Object... parameters) { Connection c = null; try { c = JdbcutilsDruid.getConnection(); return qr.update(c, sql, parameters); } catch (Exception e) { // TODO: handle exception throw new RuntimeException(e); } finally { JdbcutilsDruid.clo(null, null, c); } } // 返回多行数据(一个List) public List<T> DaoList(String sql, Class<T> cls, Object... parameters) { Connection c = null; try { c = JdbcutilsDruid.getConnection(); return qr.query(c, sql, new BeanListHandler<T>(cls), parameters); } catch (Exception e) { // TODO: handle exception throw new RuntimeException(e); } finally { JdbcutilsDruid.clo(null, null, c); } } // 返回单行数据(一个对应Bean对象) public T DaoSingeList(String sql, Class<T> cls, Object... parameters) { Connection c = null; try { c = JdbcutilsDruid.getConnection(); return qr.query(c, sql, new BeanHandler<T>(cls), parameters); } catch (Exception e) { // TODO: handle exception throw new RuntimeException(e); } finally { JdbcutilsDruid.clo(null, null, c); } } // 返回单行单个数据(一个 object) public Object DaoSinge(String sql, Object... parameters) { Connection c = null; try { c = JdbcutilsDruid.getConnection(); return qr.query(c, sql, new ScalarHandler<T>(), parameters); } catch (Exception e) { // TODO: handle exception throw new RuntimeException(e); } finally { JdbcutilsDruid.clo(null, null, c); } } }
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