jdbc.rar_JDBC增删改查_java jdbc_jdbc_jdbc 增删改查_jdbc封装

package cn.itcast.jdbc; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import cn.itcast.jdbc.domain.User; /** * * 2008-12-7 * * @author <a href="mailto:liyongibm@gmail.com">liyong</a> * */ public class ORMTest { /** * @param args * @throws Exception * @throws InvocationTargetException * @throws IllegalAccessException * @throws SQLException */ public static void main(String[] args) throws SQLException, IllegalAccessException, InvocationTargetException, Exception { User user = (User) getObject( "select id as Id, name as Name, birthday as Birthday, money as Money from user where id=1", User.class); System.out.println(user); Bean b = (Bean) getObject( "select id as Id, name as Name, birthday as Birthday, money as Money from user where id=1", Bean.class); System.out.println(b); } static List<Object> getObjects(String sql, Class clazz) throws SQLException, Exception, IllegalAccessException, InvocationTargetException { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JdbcUtils.getConnection(); ps = conn.prepareStatement(sql); rs = ps.executeQuery(); String[] colNames = getColNames(rs); List<Object> objects = new ArrayList<Object>(); Method[] ms = clazz.getMethods(); while (rs.next()) { Object object = clazz.newInstance(); for (int i = 0; i < colNames.length; i++) { String colName = colNames[i]; String methodName = "set" + colName; // Object value = rs.getObject(colName); // try { // Method m = clazz // .getMethod(methodName, value.getClass()); // if (m != null) // m.invoke(object, value); // } catch (NoSuchMethodException e) { // e.printStackTrace(); // // // } for (Method m : ms) { if (methodName.equals(m.getName())) { m.invoke(object, rs.getObject(colName)); break; } } objects.add(object); } } return objects; } finally { JdbcUtils.free(rs, ps, conn); } } private static String[] getColNames(ResultSet rs) throws SQLException { ResultSetMetaData rsmd = rs.getMetaData(); int count = rsmd.getColumnCount(); String[] colNames = new String[count]; for (int i = 1; i <= count; i++) { colNames[i - 1] = rsmd.getColumnLabel(i); } return colNames; } static Object getObject(String sql, Class clazz) throws SQLException, Exception, IllegalAccessException, InvocationTargetException { Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; try { conn = JdbcUtils.getConnection(); ps = conn.prepareStatement(sql); rs = ps.executeQuery(); String[] colNames = getColNames(rs); Object object = null; Method[] ms = clazz.getMethods(); if (rs.next()) { object = clazz.newInstance(); for (int i = 0; i < colNames.length; i++) { String colName = colNames[i]; String methodName = "set" + colName; // Object value = rs.getObject(colName); // try { // Method m = clazz // .getMethod(methodName, value.getClass()); // if (m != null) // m.invoke(object, value); // } catch (NoSuchMethodException e) { // e.printStackTrace(); // // // } for (Method m : ms) { if (methodName.equals(m.getName())) { m.invoke(object, rs.getObject(colName)); break; } } } } return object; } finally { JdbcUtils.free(rs, ps, conn); } } }