Java中的反射实现数据库操作

package com.accp.testProp; import java.sql.*; import java.util.Properties; import java.lang.reflect.Field; import java.util.Vector; public class WLTemplate { public static boolean save(Object obj) { boolean isSuccess = false; Connection conn = null; PreparedStatement pstmt = null; String left_sql = "INSERT INTO "; String right_sql = ") VALUES("; try { conn = DBConnection.getConnection(); String tableName = obj.getClass().getSimpleName(); left_sql += tableName + "("; Field[] fields = obj.getClass().getDeclaredFields(); for (int i = 0; i < fields.length; i++) { String field = fields[i].getName(); String method = "get" + field.substring(0, 1).toUpperCase() + field.substring(1, field.length()); String value = (String) obj.getClass().getMethod(method).invoke(obj); if (value != null && !value.equals("")) { left_sql += field + ","; right_sql += "'" + value + "',"; } } left_sql = left_sql.substring(0, left_sql.length() - 1); right_sql = right_sql.substring(0, right_sql.length() - 1) + ")"; // System.out.println(left_sql + right_sql); pstmt = conn.prepareStatement(left_sql + right_sql); int temp = pstmt.executeUpdate(); if (temp != 0) { isSuccess = true; } } catch (Exception ex) { ex.printStackTrace(); } finally { DBConnection.close(conn, pstmt, null); } return isSuccess; } public static boolean delete(Object obj) { boolean isSuccess = false; Connection conn = null; PreparedStatement pstmt = null; String sql = "DELETE FROM "; try { conn = DBConnection.getConnection(); String tableName = obj.getClass().getSimpleName(); sql += tableName + " WHERE "; Field[] fields = obj.getClass().getDeclaredFields(); String field = fields[0].getName(); String method = "get" + field.substring(0, 1).toUpperCase() + field.substring(1, field.length()); String value = (String) obj.getClass().getMethod(method).invoke(obj); sql += field + " = '" + value + "'"; // System.out.println(sql); pstmt = conn.prepareStatement(sql); int temp = pstmt.executeUpdate(); if (temp != 0) { isSuccess = true; } } catch (Exception ex) { ex.printStackTrace(); } finally { DBConnection.close(conn, pstmt, null); } return isSuccess; } public static boolean update(Object obj) { boolean isSuccess = false; Connection conn = null; PreparedStatement pstmt = null; String sql = "UPDATE "; try { conn = DBConnection.getConnection(); String tableName = obj.getClass().getSimpleName(); sql += tableName + " SET "; Field[] fields = obj.getClass().getDeclaredFields(); for (int i = 1; i < fields.length; i++) { String field = fields[i].getName(); String method = "get" + field.substring(0, 1).toUpperCase() + field.substring(1, field.length()); String value = (String) obj.getClass().getMethod(method).invoke(obj); if (value != null && !value.equals("")) { sql += field + " = '" + value + "', "; } } sql = sql.trim(); sql = sql.substring(0, sql.length() - 1); String id = fields[0].getName(); String id_method = "get" + id.substring(0, 1).toUpperCase() + id.substring(1, id.length()); String id_value = (String) obj.getClass().getMethod(id_method).invoke(obj); sql += " WHERE " + id + " = '" + id_value + "'"; // System.out.println(sql); pstmt = conn.prepareStatement(sql); int temp = pstmt.executeUpdate(); if (temp != 0) { isSuccess = true; } } catch (Exception ex) { ex.printStackTrace(); } finally { DBConnection.close(conn, pstmt, null); } return isSuccess; } public static Object findByPrimaryKey(Object obj) { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; Object return_obj = null; String sql = "SELECT "; try { conn = DBConnection.getConnection(); Field[] fields = obj.getClass().getDeclaredFields(); for (int i = 0; i < fields.length; i++) { String field = fields[i].getName(); sql += field + ","; } sql = sql.substring(0, sql.length() - 1); String tableName = obj.getClass().getSimpleName(); sql += " FROM " + tableName; String id = fields[0].getName(); String id_method = "get" + id.substring(0, 1).toUpperCase() + id.substring(1, id.length()); String id_value = (String) obj.getClass().getMethod(id_method).invoke(obj); sql += " WHERE " + id + " = '" + id_value + "'"; pstmt = conn.prepareStatement(sql); // System.out.println(sql); rs = pstmt.executeQuery(); while (rs.next()) { String classname = obj.getClass().getName(); Class c = Class.forName(classname); return_obj = c.newInstance(); for (int i = 0; i < fields.length; i++) { String field = fields[i].getName(); Class p = Class.forName("java.lang.String"); String method = "set" + field.substring(0, 1).toUpperCase() + field.substring(1, field.length()); obj.getClass().getMethod(method, p).invoke(return_obj, rs.getString(i + 1)); } } } catch (Exception ex) { ex.printStackTrace(); } finally { DBConnection.close(conn, pstmt, rs); } return return_obj; } public static Vector findAll(Object obj) { Vector objs = new Vector(); Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; String sql = "SELECT "; try { conn = DBConnection.getConnection(); Field[] fields = obj.getClass().getDeclaredFields(); for (int i = 0; i < fields.length; i++) { String field = fields[i].getName(); sql += field + ","; } sql = sql.substring(0, sql.length() - 1); String tableName = obj.getClass().getSimpleName(); sql += " FROM " + tableName + " WHERE "; for (int i = 1; i < fields.length; i++) { String check = fields[i].getName(); String check_method = "get" + check.substring(0, 1).toUpperCase() + check.substring(1, check.length()); String check_value = (String) obj.getClass().getMethod(check_method). invoke(obj); if(check_value == null){ check_value = ""; } sql += check + " LIKE '%" + check_value.trim() + "%' AND "; } sql = sql.trim(); sql = sql.substring(0, sql.length() - 3); pstmt = conn.prepareStatement(sql); // System.out.println(sql); rs = pstmt.executeQuery(); while (rs.next()) { String classname = obj.getClass().getName(); Class c = Class.forName(classname); Object return_obj = c.newInstance(); for (int i = 0; i < fields.length; i++) { String field = fields[i].getName(); Class p = Class.forName("java.lang.String"); String method = "set" + field.substring(0, 1).toUpperCase() + field.substring(1, field.length()); obj.getClass().getMethod(method, p).invoke(return_obj, rs.getString(i + 1)); } objs.add(return_obj); } } catch (Exception ex) { ex.printStackTrace(); } finally { DBConnection.close(conn, pstmt, rs); } return objs; } public static boolean saveOrUpdate(Object obj){ boolean isSuccess = false; try { if(findByPrimaryKey(obj) == null){ isSuccess = save(