Android Sqlite 与 dao

来源：互联网发布：越南南海知乎编辑：程序博客网时间：2024/06/07 01:52

public static <T> List<T> readAllTrans(T t, DBManager dbHelper, String tableName) {

       dbHelper.openDatabase();
       SQLiteDatabase db = dbHelper.getDatabase();
       Cursor cursor = db.query(tableName, null, null, null, null, null, null);
       List<T> dataList = new ArrayList<T>();

       //表中各项名称
       List<String> columnNames = new ArrayList<String>(Arrays.asList(cursor.getColumnNames()));
       columnNames.remove("id");
       //对表中各项进行排序，反射得到的set方法是按升序排列，便于匹配
       Collections.sort(columnNames);
       System.out.println("columnNames2" + columnNames.size());

       try {
           Class<? extends Object> clazz = t.getClass();
           Method[] declaredMethods = clazz.getDeclaredMethods();
           List<Method> allSetMethods = new ArrayList<Method>();
           List<Method> setMethods = new ArrayList<Method>();

           //获取所有set方法
           for(int i = 0; i < declaredMethods.length; i++){
               String methodName = declaredMethods[i].getName();
               if(methodName.startsWith("set") ){
                   allSetMethods.add(declaredMethods[i]);

               }
           }
           //获取与数据库ColumnName相符的set方法
           for(int i = 0; i < columnNames.size(); i++){
               for(int j = i; j < allSetMethods.size(); j++){
                   String methodName = allSetMethods.get(j).getName();
                   if( columnNames.get(i).equalsIgnoreCase(methodName.substring(3, methodName.length()))){
                       setMethods.add(allSetMethods.get(j));
                       continue;
                   }
               }
           }
           System.out.println("columnNames.size() : " + columnNames.size() + "setMethods.size() : " + setMethods.size());
           if (cursor != null && cursor.moveToFirst()) {
                do {

                   t = (T) clazz.newInstance();
                   for(int i = 0; i < setMethods.size(); i++ ){
                       Method method = setMethods.get(i);
                       Class<?>[] parameterTypes = method.getParameterTypes();
                       int columnIndex = cursor.getColumnIndex(columnNames.get(i));
                      if (parameterTypes[0] == String.class) {
                         method.invoke(t,cursor.getString(columnIndex));
                     }else if (parameterTypes[0] == int.class) {
                         method.invoke(t, cursor.getInt(columnIndex));
                     }else if (parameterTypes[0] == long.class) {
                         method.invoke(t, cursor.getLong(columnIndex));
                     }else if (parameterTypes[0] == byte.class) {
                         method.invoke(t, (byte)cursor.getInt(columnIndex));
                     }else if (parameterTypes[0] == boolean.class) {
                         method.invoke(t, cursor.getInt(columnIndex) == 0 ? false:true);
                     }else if(parameterTypes[0] == byte[].class){
                       method.invoke(t, cursor.getBlob(columnIndex));

                      }

                   }
                   dataList.add(t);
                }while (cursor.moveToNext());

           }

       } catch (InstantiationException e ) {
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           e.printStackTrace();
       } catch (IllegalArgumentException e) {
           e.printStackTrace();
       } catch (InvocationTargetException e) {
           e.printStackTrace();
       }
       dbHelper.closeDatabase();
       return dataList;

       }

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