Sqlite 反射机制封装数据库

概述public class SqliteDAO{ static final String tag="DAO"; /** * 访问的数据库 */ private SQLiteDatabase db; /** * 数据库打开辅助类 */ private static PADoctorSQLiteHelper paDoct

public class sqliteDAO{    static final String tag="DAO";    /**     * 访问的数据库     */    private sqliteDatabase db;    /**     * 数据库打开辅助类     */    private static PADoctorsqliteHelper paDoctorsqliteHelper;    private static long curUserID;    /**     * 数据插入冲突处理方式:     * 0-忽略     * 1-抛出异常     * 2-替换数据     */    private int conflictType = 2;    public sqliteDAO(Context c,long userID){        if (paDoctorsqliteHelper == null || userID != curUserID) {            curUserID = userID;            String prefix = "";            try {                prefix = c.getExternalfilesDir(null).getabsolutePath() + "/";            } catch (Exception e) {                prefix = "";            }            paDoctorsqliteHelper = new PADoctorsqliteHelper(c,prefix+"u"+curUserID+".msg",null,1);        }        db = paDoctorsqliteHelper.getWritableDatabase();    }    public voID close() {        //db.close();    }    public sqliteDatabase getsqliteDatabase(){        return db;    }    /**     * 插入对象到数据库,存储对象的所有字段到数据库的对应字段,包括NulL字段.     * @param entity  待插入的对象     * @return 如果插入数据库成功则返回该对象,否则返回NulL     */    public <T> T insert(T entity){        return insert(entity,false);    }    /**     * 插入对象到数据库,仅存储对象的非空字段到数据库,对象的NulL字段将被忽略.     * @param entity 待插入的对象     * @return 如果插入数据库成功则返回该对象,否则返回NulL     */    public <T> T insertSelective(T entity){        return insert(entity,true);    }    private <T> T insert(T entity,boolean selective){        ContentValues values=getContentValues(entity,selective);//        T exist_obj=this.loadByPrimaryKey(entity);//        if(exist_obj!=null){//            return exist_obj;//        }        long r;        if(conflictType == 2){            r = db.replace(gettablename(entity),values);        }else{            r = db.insert(gettablename(entity),values);        }        if(r >= 0){            return entity;        }        return null;    }    /**     * 根据主键删除数据     * @param entity 待删除的对象,主键只必须设置.     * @return     */    public <T> int delete(T entity){        Object[] args=getPrimarySelectionAndArgs(entity);        return db.delete(gettablename(entity),(String)args[0],(String[])args[1]);    }    /**     *     * @param entity     * @param whereClause     * @param whereArgs     * @return the number of rows affected if a whereClause is passed in,0 otherwise.     * To remove all rows and get a count pass "1" as the whereClause.     */    public <T> int deleteByWhereClause(T entity,String whereClause,String[] whereArgs) {        return db.delete(gettablename(entity),whereClause,whereArgs);    }    /**     * 根据主键从数据库载入一条记录到对象     * @param entity 数据实体(必须初始化主键字段)     * @return 成功则返回的该数据库实体,失败则返回NulL     */    public <T> T loadByPrimaryKey(T entity){        Object[] args=getPrimarySelectionAndArgs(entity);        Cursor cursor=db.query(gettablename(entity),(String[])args[1],null);        try{            if(cursor.movetoNext()){                T db_entity=getEntity(cursor,entity);                return db_entity;            }else{                return null;            }        }finally{            cursor.close();        }    }    @SuppressWarnings("unchecked")    public <T> List<T> query(T entity,String[] columns,String selection,String[] selectionArgs,String groupBy,String having,String orderBy,String limit){        List<T> entitIEs = new ArrayList<T>();        Cursor cursor = db.query(gettablename(entity),columns,selection,selectionArgs,groupBy,having,orderBy,limit);        try{            if(cursor!=null && cursor.movetoFirst()){                T obj=(T)entity.getClass().newInstance();                getEntity(cursor,obj);                entitIEs.add(obj);                while(cursor.movetoNext()) {                    obj=(T)entity.getClass().newInstance();                    getEntity(cursor,obj);                    entitIEs.add(obj);                }            }            return entitIEs;        }catch(Exception e){            Log.e(tag,""+e,e);            return entitIEs;        }finally{            cursor.close();        }    }    @SuppressWarnings("unchecked")     public <T> List<T> loadAll(T entity,String limit){        List<T> entitIEs=new ArrayList<T>();        Cursor cursor=db.query(gettablename(entity),e);            return entitIEs;        }finally{            cursor.close();        }    }    /**     * 更新数据库实体,更新对象的所有字段到数据库的对应字段,包括NulL字段.     * @param entity 待更新的对象(必须包含主键)     * @return 成功更新的记录数     */    public int updateByPrimaryKey(Object entity){        return updateByPrimaryKey(entity,false);    }    /**     * 更新数据库实体,仅更新对象的非空字段到数据库的对应字段,对象的NulL字段将被忽略.     * @param entity 待更新的对象(必须包含主键)     * @return 成功更新的记录数     */    public int updateByPrimaryKeySelective(Object entity){        return updateByPrimaryKey(entity,true);    }    private int updateByPrimaryKey(Object entity,selective);        Object[] args=getPrimarySelectionAndArgs(entity);        int r=db.update(gettablename(entity),values,(String[])args[1]);        return r;    }    /**     * 从对象中解析出主键字段,以及主键字段对应的值     * @param entity     * @return     */    private Object[] getPrimarySelectionAndArgs(Object entity){        Object[] ret=new Object[2];        String selection=null;        List<String> args=new ArrayList<String>();        try{            Class<?> entity_class=entity.getClass();            FIEld[] fs=entity_class.getDeclaredFIElds();            for(FIEld f:fs){                if(isPrimaryKey(f)){                    Method get=getgetmethod(entity_class,f);                    if(get!=null){                        Object o=get.invoke(entity);                        String value=null;                        if(o!=null){                            value=o.toString();                            if(selection==null){                                selection=f.getname()+"=?";                            }else{                                selection+=" AND "+f.getname()+"=?";                            }                            args.add(value);                        }else{                            throw new RuntimeException("Primary key: "+f.getname()+" must not be null");                        }                    }                }            }            if(selection==null){                throw new RuntimeException("Primary key not found!");            }            ret[0]=selection;            ret[1]=args.toArray(new String[args.size()]);            return ret;        }catch(Exception e){            throw new RuntimeException(e.getMessage(),e);        }    }    /**     * 将对象转换为ContentValues     * @param entity     * @param selective     * @return     */    private ContentValues getContentValues(Object entity,boolean selective){        ContentValues values=new ContentValues();        try{            Class<?> entity_class=entity.getClass();            FIEld[] fs=entity_class.getDeclaredFIElds();            for(FIEld f:fs){                if(isTransIEnt(f)==false){                    Method get=getgetmethod(entity_class,f);                    if(get!=null){                        Object o=get.invoke(entity);                        if(!selective || (selective && o!=null)){                            String name=f.getname();                            Class<?> type=f.getType();                            if(type==String.class){                                values.put(name,(String)o);                            }else if(type==int.class || type==Integer.class){                                values.put(name,(Integer)o);                            }else if(type==float.class || type==float.class){                                values.put(name,(float)o);                            }else if(type==long.class || type==Long.class){                                values.put(name,(Long)o);                            }else if(type==Date.class){                                values.put(name,datetimetoString((Date)o));                            }else{                                values.put(name,o.toString());                            }                        }                    }                }            }            return values;        }catch(Exception e){            throw new RuntimeException(e.getMessage(),e);        }    }    /**     * 将数据库记录转换为对象     *     * @param cursor     * @param entity     * @return     */    private <T> T getEntity(Cursor cursor,T entity){        try{            Class<?> entity_class=entity.getClass();            FIEld[] fs=entity_class.getDeclaredFIElds();            for(FIEld f:fs){                int index=cursor.getColumnIndex(f.getname());                if(index>=0){                    Method set=getSetMethod(entity_class,f);                    if(set!=null){                        String value=cursor.getString(index);                        if(cursor.isNull(index)){                            value=null;                        }                        Class<?> type=f.getType();                        if(type==String.class){                            set.invoke(entity,value);                        }else if(type==int.class || type==Integer.class){                            set.invoke(entity,value==null?(Integer)null:Integer.parseInt(value));                        }else if(type==float.class || type==float.class){                            set.invoke(entity,value==null?(float)null:float.parsefloat(value));                        }else if(type==long.class || type==Long.class){                            set.invoke(entity,value==null?(Long)null:Long.parseLong(value));                        }else if(type==Date.class){                            set.invoke(entity,value==null?(Date)null:stringToDateTime(value));                        }else{                            set.invoke(entity,value);                        }                    }                }            }            return entity;        }catch(Exception e){            throw new RuntimeException(e.getMessage(),e);        }    }    private String datetimetoString(Date d){        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        if(d!=null){            return sdf.format(d);        }        return null;    }    private Date stringToDateTime(String s){        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        if(s!=null){            try {                return sdf.parse(s);            } catch (ParseException e) {                Log.e(tag,"解析时间错误: "+s,e);            }        }        return null;    }    private Method getgetmethod(Class<?> entity_class,FIEld f){        String fn=f.getname();        String mn="get"+fn.substring(0,1).toupperCase()+fn.substring(1);        try{            return entity_class.getDeclaredMethod(mn);        }catch(NoSuchMethodException e){            Log.w(tag,"Method: "+mn+" not found.");            return null;        }    }    private Method getSetMethod(Class<?> entity_class,FIEld f){        String fn=f.getname();        String mn="set"+fn.substring(0,1).toupperCase()+fn.substring(1);        try{            return entity_class.getDeclaredMethod(mn,f.getType());        }catch(NoSuchMethodException e){            Log.w(tag,"Method: "+mn+" not found.");            return null;        }    }    /**     * 检查是否为主键字段     */    private boolean isPrimaryKey(FIEld f){        Annotation an=f.getAnnotation(ID.class);        if(an!=null){            return true;        }        return false;    }    private boolean isTransIEnt(FIEld f){        Annotation an=f.getAnnotation(TransIEnt.class);        if(an!=null){            return true;        }        return false;    }    private String gettablename(Object entity){        table table=entity.getClass().getAnnotation(table.class);        String name= table.name();        return name;    }    public int getConflictType() {        return conflictType;    }    public voID setConflictType(int conflictType) {        this.conflictType = conflictType;    }}

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