jdbc简易泛型dao(四)
bleName(clazz);
//获得字段
List
List
List placeholders = new ArrayList();//占位符
String idFieldName = "";
Object idFieldValue = "";
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
PropertyDescriptor pd = new PropertyDescriptor(field.getName(),t.getClass());
if (field.isAnnotationPresent(Id.class)) {
idFieldName = field.getAnnotation(Id.class).value();
idFieldValue = pd.getReadMethod().invoke(t);
} else if(field.isAnnotationPresent(Column.class)) {
fieldNames.add(field.getAnnotation(Column.class).value());
fieldValues.add(pd.getReadMethod().invoke(t));
placeholders.add(" ");
}
}
//ID作为更新条件，放在集合中的最后一个元素
fieldNames.add(idFieldName);
fieldValues.add(idFieldValue);
placeholders.add(" ");
//拼接sql
StringBuilder sql = new StringBuilder("");
sql.append("update ").append(tableName).append(" set ");
int index = fieldNames.size() - 1;
for (int i = 0; i < index; i++) {
sql.append(fieldNames.get(i)).append("=").append(placeholders.get(i)).append(",");
}
sql.deleteCharAt(sql.length()-1).append(" where ").append(fieldNames.get(index)).append("=").append(" ");
//设置SQL参数占位符的值
PreparedStatement ps = JdbcDaoHelper.getConnection().prepareStatement(sql.toString());
setParameter(fieldValues, ps, false);
//执行SQL
ps.execute();
JdbcDaoHelper.release(ps, null);
System.out.println(sql + "\n" + clazz.getSimpleName() + "修改成功.");
}
@Override
public T get(Object id,Class clazz) throws Exception {
String idFieldName = "";
Field[] fields = clazz.getDeclaredFields();
boolean flag = false;
for (Field field : fields) {
if (field.isAnnotationPresent(Id.class)) {
idFieldName = field.getAnnotation(Id.class).value();
flag = true;
break;
}
}
if (!flag) {
throw new NotFoundAnnotationException(clazz.getName() + " object not found id property.");
}
//拼装SQL
Map sqlWhereMap = new HashMap();
sqlWhereMap.put(TABLE_ALIAS + "." + idFieldName, id);
List list = findAllByConditions(sqlWhereMap, clazz);
return list.size() > 0 list.get(0) : null;
}
@Override
public List findAllByConditions(Map sqlWhereMap,Class clazz) throws Exception {
List list = new ArrayList();
String tableName = getTableName(clazz);
String idFieldName = "";
//存储所有字段的信息
//通过反射获得要查询的字段
StringBuffer fieldNames = new StringBuffer();
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
String propertyName = field.getName();
if (field.isAnnotationPresent(Id.class)) {
idFieldName = field.getAnnotation(Id.class).value();
fieldNames.append(TABLE_ALIAS + "." + idFieldName)
.