import java.lang.reflect.Field; import java.sql.Connection; import java.sql.DatabaseMetaData; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.util.ArrayList; public class RDao { /** * 通过表明获取数据库中表的列明 * @param tableName * @return */ public ArrayList<String> getAllColumn(String tableName){ ArrayList<String> ar = new ArrayList<String>(); Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; //1=2不成立只能查出来列明 String sql = "select * from "+tableName+" where 1=2"; try { ps = conn.prepareStatement(sql); rs = ps.executeQuery(); ResultSetMetaData metedata = rs.getMetaData(); int colum = metedata.getColumnCount(); for (int i=1;i<=colum;i++) { String columnName = metedata.getColumnName(i); ar.add(columnName); } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps, rs); } return ar; } /** * 通过元数据获得数据列明,数据类型等 * * 两者的区别R可以获得SQL语句查询出来的所有的列明 * D只可以获取单表列明以及列的所有的属性 * * @param tableName * @return */ public ArrayList<String> getAllColumns(String tableName){ ArrayList<String> ar = new ArrayList<String>(); Connection conn = BaseConnection.getConnection(); ResultSet rs = null; try { //数据库元数据对象,就是数据库数据对象 DatabaseMetaData dbm = conn.getMetaData(); rs = dbm.getColumns(null, "%", tableName, "%"); while (rs.next()) { String columnName = rs.getString("COLUMN_NAME"); String columnType = rs.getString("TYPE_NAME"); String datasize = rs.getString("COLUMN_SIZE"); String digits = rs.getString("DECIMAL_DIGITS"); String nullable = rs.getString("NULLABLE"); ar.add(columnName); } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, rs); } return ar; } public boolean insert(Object ob){ boolean b = false; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; Class cl = ob.getClass(); Field[] fi = cl.getDeclaredFields(); ArrayList<String >col = getAllColumn(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); StringBuffer sb1 = new StringBuffer(); sb.append("insert into "); sb.append(cl.getSimpleName()); sb.append("("); for (int i=1;i<col.size();i++) { sb.append(col.get(i)); sb1.append("?"); if (i != col.size()-1) { sb.append(","); sb1.append(","); } } sb.append(")values("); sb.append(sb1); sb.append(")"); try { ps = conn.prepareStatement(sb.toString()); for (int i=1;i<col.size();i++) { for (Field ff:fi) { if (ff.getName().equals(col.get(i))) { ff.setAccessible(true); ps.setObject(i, ff.get(ob)); break; } } } int a = ps.executeUpdate(); if (a > 0) { b = true; } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps); } return b; } //需求是现在有一个表,这个表是一个订单表(订单号,订单时间,订单人) // 33 20150101 zhang // 从表订单详细表 编号 订单号 商品名 数量 // 1 33 ku 2 // 2 33 qun 3 //依次订单有好多数据,我们插入数据的时候就是先插入订单表,然后再插入订单详细表,再插入订单详细表的时候你是需要订单表中的订单号的。 public int insertGetKey(Object ob) { int id = 0; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Class cl = ob.getClass(); Field[] fi = cl.getDeclaredFields(); ArrayList<String >col = getAllColumn(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); StringBuffer sb1 = new StringBuffer(); sb.append("insert into "); sb.append(cl.getSimpleName()); sb.append("("); for (int i=1;i<col.size();i++) { sb.append(col.get(i)); sb1.append("?"); if (i != col.size()-1) { sb.append(","); sb1.append(","); } } sb.append(")values("); sb.append(sb1); sb.append(")"); try { ps = conn.prepareStatement(sb.toString()); for (int i=1;i<col.size();i++) { for (Field ff:fi) { if (ff.getName().equals(col.get(i))) { ff.setAccessible(true); ps.setObject(i, ff.get(ob)); break; } } } int a = ps.executeUpdate(); if (a > 0) { ////获得主键,主键必须是递增,还有必须是添加的方法才能获得主键 rs = ps.getGeneratedKeys(); if (rs.next()) { id = rs.getInt(1); } } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps); } return id; } //删除自己写根据id删除 public boolean deleteById(Class cl,int id) { boolean b = false; Object ob = null; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; Field[] fi = cl.getDeclaredFields(); //获得表中的所有列 ArrayList<String> col = getAllColumns(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("delete "); sb.append("from "); sb.append(cl.getSimpleName()); sb.append("where"); sb.append(col.get(0)); sb.append("?"); try { ps = conn.prepareStatement(sb.toString()); ps.setInt(1, id); int a = ps.executeUpdate(); if (a>0) { b = true; } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps); } return b; } /** * 这个方法是不需要的,没有意义,直接忘记,还获取不到值 * @param ob * @return */ public int updateGetKey(Object ob){ int id = 0; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Class cl = ob.getClass(); Field[] fi = cl.getDeclaredFields(); ArrayList<String >col = getAllColumn(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("update "); sb.append(cl.getSimpleName()); sb.append(" set"); for (int i=1;i<col.size();i++) { sb.append(col.get(i)); sb.append("?"); if (i != col.size()-1) { sb.append(","); } } sb.append(" where"); sb.append(col.get(0)); sb.append("=?"); try { ps = conn.prepareStatement(sb.toString()); for (int i=1;i<col.size();i++) { for (Field ff:fi) { if (ff.getName().equals(col.get(i))) { ff.setAccessible(true); ps.setObject(i, ff.get(ob)); break; } } } fi[0].setAccessible(true); ps.setObject(col.size(), fi[0].get(ob)); int a = ps.executeUpdate(); if (a > 0) { //获得主键,主键必须是递增,还有必须是添加的方法才能获得主键 rs = ps.getGeneratedKeys(); if (rs.next()) { id = rs.getInt(1); } } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps); } return id; } public boolean update(Object ob){ boolean b = false; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; Class cl = ob.getClass(); Field[] fi = cl.getDeclaredFields(); ArrayList<String >col = getAllColumn(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("update "); sb.append(cl.getSimpleName()); sb.append(" set"); for (int i=1;i<col.size();i++) { sb.append(col.get(i)); sb.append("?"); if (i != col.size()-1) { sb.append(","); } } sb.append(" where"); sb.append(col.get(0)); sb.append("=?"); try { ps = conn.prepareStatement(sb.toString()); for (int i=1;i<col.size();i++) { for (Field ff:fi) { if (ff.getName().equals(col.get(i))) { ff.setAccessible(true); ps.setObject(i, ff.get(ob)); break; } } } fi[0].setAccessible(true); ps.setObject(col.size(), fi[0].get(ob)); int a = ps.executeUpdate(); if (a > 0) { b = true; } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps); } return b; } /** * * @param cl * @param name 数据库中的列明 * @param value * @return */ public ArrayList getListByLike(Class cl,String name,Object value) { ArrayList ar = new ArrayList(); Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Field[] fi = cl.getDeclaredFields(); ArrayList<String> col = getAllColumns(cl.getName()); StringBuffer sb = new StringBuffer(); sb.append("select "); for (int i=0;i<col.size();i++) { sb.append(col.get(i)); if (i != col.size()-1) { sb.append(","); } } sb.append(" from"); sb.append(cl.getSimpleName()); sb.append(" where "); sb.append(name); sb.append(" like ‘%"); sb.append(value); sb.append("%‘"); //like 语句不支持占位符 try { ps = conn.prepareStatement(sb.toString()); rs = ps.executeQuery(); while (rs.next()) { Object obj = cl.newInstance(); for (String str:col) { for (Field ff:fi) { if (str.equals(ff.getName())) { ff.setAccessible(true); ff.set(obj, rs.getObject(ff.getName())); break; } } } ar.add(obj); } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps, rs); } return ar; } /** * 该方法用于所有的查询 * 注意:尽量保证链接表中数据 除了主外键关联的外,尽量不要使用重复的表列名 * @param 查询出来的数据放到那个类中 实体类中 * @param sql 查询的sql语句 * @param obs 所有的条件 * @return */ public ArrayList getListBySqlX(Class cl,String sql,Object[]obs){ Connection conn = BaseConnection.getConnection(); ArrayList ar = new ArrayList(); PreparedStatement ps = null; ResultSet rs = null; Field[] fi = cl.getDeclaredFields(); ArrayList<String> col = new ArrayList<String>(); try { ps = conn.prepareStatement(sql); //获得数据表中的列 ResultSetMetaData metaData = rs.getMetaData(); int column = metaData.getColumnCount(); for (int i=1;i<=column;i++) { String columnName = metaData.getColumnName(i); col.add(columnName); } for (int i=0;i<obs.length;i++) { ps.setObject(i+1, obs[i]); } rs = ps.executeQuery(); while (rs.next()) { Object ob = cl.newInstance(); for (String str:col) { for (Field ff:fi) { if (str.equals(ff.getName())) { ff.setAccessible(true); ff.set(ob, rs.getObject(ff.getName())); break; } } } ar.add(ob); } } catch (Exception e) { // TODO: handle exception }finally{ BaseConnection.close(conn, ps, rs); } return ar; } public ArrayList getListBySome(Class cl,String name,Object value) { ArrayList ar = new ArrayList(); Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Field[] fi = cl.getDeclaredFields(); //获得表中的所有列 ArrayList<String> col = getAllColumns(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("select "); for (int i=0;i<col.size();i++) { sb.append(col.get(i)); if (i != col.size()-1) { sb.append(","); } } sb.append("from "); sb.append(cl.getSimpleName()); sb.append(" where "); sb.append(name); sb.append(" =? "); try { ps = conn.prepareStatement(sb.toString()); ps.setObject(1, value); rs = ps.executeQuery(); while (rs.next()) { Object obj = cl.newInstance(); for (String str:col) { for (Field ff:fi) { if (str.equals(ff.getName())) { ff.setAccessible(true); ff.set(obj, rs.getObject(ff.getName())); break; } } } ar.add(obj); } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps, rs); } return ar; } public Object getObById(Class cl,int id){ Object ob = null; Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Field[] fi = cl.getDeclaredFields(); //获得表中的所有列 ArrayList<String> col = getAllColumns(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("select "); for (int i=0;i<col.size();i++) { sb.append(col.get(i)); if (i != col.size()-1) { sb.append(","); } } sb.append("from "); sb.append(cl.getSimpleName()); sb.append("where"); sb.append(col.get(0)); sb.append("?"); try { ps = conn.prepareStatement(sb.toString()); ps.setInt(1, id); rs = ps.executeQuery(); while (rs.next()) { Object obj = cl.newInstance(); for (String str:col) { for (Field ff:fi) { if (str.equals(ff.getName())) { ff.setAccessible(true); ff.set(obj, rs.getObject(ff.getName())); break; } } } } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps, rs); } return ob; } public ArrayList getList(Class cl){ ArrayList ar = new ArrayList(); Connection conn = BaseConnection.getConnection(); PreparedStatement ps = null; ResultSet rs = null; Field[] fi = cl.getDeclaredFields(); //获得表中的所有列 ArrayList<String> col = getAllColumns(cl.getSimpleName()); StringBuffer sb = new StringBuffer(); sb.append("select"); for (int i=0;i<col.size();i++) { sb.append(col.get(i)); if (i != col.size()-1) { sb.append(","); } } sb.append("from"); sb.append(cl.getSimpleName()); try { ps = conn.prepareStatement(sb.toString()); rs = ps.executeQuery(); while (rs.next()) { Object obj = cl.newInstance(); for (String str:col) { for (Field ff:fi) { if (str.equals(ff.getName())) { ff.setAccessible(true); ff.set(obj, rs.getObject(ff.getName())); break; } } } ar.add(obj); } } catch (Exception e) { // TODO: handle exception }finally { BaseConnection.close(conn, ps, rs); } return ar; } public static void main(String[] args) { } }
时间: 2024-10-14 02:09:53