Java毕业设计基于Servlet+JQuery+Ajax实现的小区物业管理系统源代码+数据库，采用MVC模式

package com.example.pms.Common; import com.example.pms.Bean.Page; import java.lang.reflect.Field; import java.util.ArrayList; import java.util.Arrays; import static com.example.pms.Common.MethodEnum.*; // TODO 待完善 public class SQLHelper { private final StringBuilder sql; private final ArrayList<Object> params; public SQLHelper() { sql = new StringBuilder(); params = new ArrayList<>(); } /** * 将obj转换成SQL语句与参数, 用于查询对应的条件结果的数量 * * @param table 查询表名 * @param objClazz obj对象 * @param clazz obj的类 */ public void queryCount(String table, Object objClazz, Class<?> clazz) { sql.append("SELECT COUNT(*) FROM ").append(table).append(" "); where(); conditions(objClazz, clazz); } /** * 查询一个对象 * @param table 表名 * @param obj mapper对象 * @param objClazz mapper对象类 */ public void queryForObject(String table, Object obj, Class<?> objClazz) { sql.append("SELECT * FROM ").append(table).append(" "); where(); conditions(obj, objClazz); } /** * 将obj和PageBean转换成SQL语句与参数, 用于查询对应的条件结果 * * @param table 查询表名 * @param obj obj对象 * @param objClazz obj的类 * @param page Page * @param orderBy 查询结果以什么列名排序 */ public void query(String table, Object obj, Class<?> objClazz, Page page, String orderBy) { sql.append("SELECT * FROM ").append(table).append(" "); where(); conditions(obj, objClazz); pageConditions(page, orderBy); } /** * 将obj和PageBean转换成SQL语句与参数, 用于查询对应的条件结果 * * @param selects 查询语句 * @param obj obj对象 * @param objClazz obj的类 * @param page Page * @param orderBy 查询结果以什么列名排序 * @param joins 多个Join语句 */ public void Query(String selects, String from, Object obj, Class<?> objClazz, Page page, String orderBy, String... joins) { sql.append(" ").append(selects).append(" "); sql.append(" ").append(from).append(" "); for (String join : joins) sql.append(" ").append(join).append(" "); where(); conditions(obj, objClazz); pageConditions(page, orderBy); } /** * @param table 插入表名 * @param bean 插入的对象 * @param beanClazz 插入对象的类 */ public void insert(String table, Object bean, Class<?> beanClazz) { sql.append("INSERT INTO ").append(table).append(" "); ArrayList<String> cols = new ArrayList<>(); ArrayList<String> values = new ArrayList<>(); try { Field[] fields = beanClazz.getDeclaredFields(); for (Field field : fields) { field.setAccessible(true); SQLCondition conditions = field.getAnnotation(SQLCondition.class); if (field.isAnnotationPresent(SQLCondition.class) && contains(insert, conditions.method())) { String key = field.getName(); Object val = field.get(bean); cols.add(key); values.add("?"); params.add(val); } } } catch (IllegalAccessException e) { throw new RuntimeException(e); } String colsStr = String.join(",", cols); String valuesStr = String.join(",", values); sql.append("(").append(colsStr).append(")"); sql.append(" VALUES (").append(valuesStr).append(")"); } /** * @param table 插入表名 * @param obj 插入的对象 * @param objClazz 插入对象的类 * @param pkName 主键的列名 */ public void update(String table, Object obj, Class<?> objClazz, String pkName) { sql.append("UPDATE ").append(table).append(" "); ArrayList<String> keys = new ArrayList<>(); Object pkValue = null; try { Field[] fields = objClazz.getDeclaredFields(); for (Field field : fields) { field.setAccessible(true); SQLCondition conditions = field.getAnnotation(SQLCondition.class); if (field.isAnnotationPresent(SQLCondition.class) && contains(update, conditions.method())) { String key = field.getName(); Object val = field.get(obj); if (key.equals(pkName)) { pkValue = val; continue; } keys.add(" " + key + " = ? "); params.add(val); } } } catch (IllegalAccessException e) { throw new RuntimeException(e); } String colsStr = String.join(",", keys); sql.append("SET ").append(colsStr).append(" "); sql.append("WHERE ").append(pkName).append(" = ? "); assert (pkValue != null); params.add(pkValue); } /** * @param table 插入表名 * @param obj 插入的对象 * @param objClazz 插入对象的类 * @param pkName 主键的列名 */ public void delete(String table, Object obj, Class<?> objClazz, String pkName) { sql.append("DELETE ").append(table).append(" "); Object pkValue = null; try { Field[] fields = objClazz.getDeclaredFields(); for (Field field : fields) { field.setAccessible(true); SQLCondition conditions = field.getAnnotation(SQLCondition.class); if (field.isAnnotationPresent(SQLCondition.class) && contains(delete, conditions.method())) { String key = field.getName(); Object val = field.get(obj); if (key.equals(pkName)) { pkValue = val; break; } } } } catch (IllegalAccessException e) { throw new RuntimeException(e); } sql.append("WHERE ").append(pkName).append(" = ").append(pkValue); } /** * 拼接条件 key [like,=] [%value%,value] * * @param key 条件名 * @param compareOperator like 或者 = * @param value 参数 */ private void doOperation(String key, String compareOperator, Object value) { sql.append(" ").append(key).append(" ").append(compareOperator).append(" ? "); String param = ""; if ("like".equalsIgnoreCase(compareOperator)) param = "%" + value + "%"; else if ("=".equals(compareOperator)) param = value.toString(); params.add(param); } /** * 拼接条件 [and,or] key [like,=] [%value%,value] * * @param logicOperator and 或者 or * @param key 条件名 * @param compareOperator like 或者 = * @param value 参数 */ private void append(String logicOperator, String key, String compareOperator, Object value) { if ("or".equalsIgnoreCase(logicOperator)) { Object[] values = (Object[]) value; if (values != null && values.length > 1) { sql.append(" and ("); for (Object val : values) { doOperation(key, compareOperator, val); sql.append(" or "); } sql.append(" 1 = 0) "); } } else if ("and".equalsIgnoreCase(logicOperator)) { if (value != null && !"".equals(value)) { sql.append(" and "); doOperation(key, compareOperator, value); } } } /**