前言
原來在項目中經常使用SqliteopenHelper這個類來實現數據庫的增刪改查,但是使用它非常的繁瑣,需要寫很多啰嗦的代碼。所以面向對象數據庫框架的設計是解決上述問題的辦法。
1.OOP數據庫設計UML類圖
角色：
- BaseDaoFactory： 用來創建數據庫和初始化數據庫
- IBaseDao： 增刪改查方法接口
- BaseDao： 實現增刪改查方法的抽象模板類(子類方法UserDao增刪改查方法在該類實現)
- Bean： 使用注解方式來定義表中相關字段名和類型，如UserBean
- ConcreteDao： 創建表，定相關義字段及其長度，（UserDao）和UserBean中的字段對應
- Client： 調用類，如Activity
2.各角色實現
BaseDaoFactory：
public class BaseDaoFactory {
private static BaseDaoFactory instance = new BaseDaoFactory();
private String sqliteDatabasePath;
private SQLiteDatabase sqLiteDatabase;
public BaseDaoFactory() {
sqliteDatabasePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/teacher.db";
openDatabase();
}
public static BaseDaoFactory getInstance() {
return instance;
}
public synchronized <T extends BaseDao<M>, M> T getDataHelper(Class<T> clazz, Class<M> entityClass) {
BaseDao baseDao = null;
try {
baseDao = clazz.newInstance();
baseDao.init(entityClass, sqLiteDatabase);
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return (T) baseDao;
}
/**
* targetSdkVersion 大于22時 要申請存儲讀寫權限
*/
//打開數據庫操作
private void openDatabase() {
this.sqLiteDatabase = SQLiteDatabase.openOrCreateDatabase(sqliteDatabasePath, null);
}
}
IBaseDao：
public interface IBaseDao<T>{
/**
* @param entity
* @return
*/
Long insert(T entity);
/**
* 更新數據
* @param entity
* @param where
* @return
*/
int update(T entity,T where);
/**
* 刪除數據
* @param where
* @return
*/
int delete(T where);
List<T> query(T where);
List<T> query(T where,String orderBy,Integer startIndex,Integer limit);
}
BaseDao：
/**
* Created by Xionghu on 2018/2/2.
* Desc: 真正和底層打交道
*
* @param <T>
*/
public abstract class BaseDao<T> implements IBaseDao<T> {
/**
* 持有數據庫操作類的引用
*/
private SQLiteDatabase database;
/**
* 保證實例化一次
*/
private boolean isInit = false;
/**
* 持有操作數據表所對應的Java類型
* User
*/
private Class<T> entityClass;
/**
* 維護這表名與成員變量名的映射關系
* key ---->表名
* value ---->Field
*/
private HashMap<String, Field> cacheMap;
private String tableName;
/**
* @param entity
* @param sqLiteDatabase
* @return 實例化一次
*/
protected synchronized boolean init(Class<T> entity, SQLiteDatabase sqLiteDatabase) {
if (!isInit) {
entityClass = entity;
Log.d("sqlite", entityClass.getSimpleName());
database = sqLiteDatabase;
if (entity.getAnnotation(DbTable.class) == null) {
tableName = entity.getClass().getSimpleName();
} else {
tableName = entity.getAnnotation(DbTable.class).value();
}
if (!database.isOpen()) {
return false;
}
if (!TextUtils.isEmpty(createTable())) {
database.execSQL(createTable());
}
cacheMap = new HashMap<>();
initCacheMap();
isInit = true;
}
return isInit;
}
/**
* 維護映射關系
*/
private void initCacheMap() {
String sql = "select * from " + this.tableName + " limit 1 , 0 ";
Cursor cursor = null;
try {
cursor = database.rawQuery(sql, null);
/**
* 表的列名數組
*/
String[] columnNames = cursor.getColumnNames();
/**
* 拿到Field數組
*/
Field[] colmunFields = entityClass.getFields();
for (Field field : colmunFields) {
field.setAccessible(true);
}
/**
* 開始找對應關系
*/
for (String colmunName : columnNames) {
/**
* 如果找到對應的Filed就賦值給他
* User
*/
Field colmunFiled = null;
for (Field field : colmunFields) {
String fileName = null;
if (field.getAnnotation(DbFiled.class) != null) {
fileName = field.getAnnotation(DbFiled.class).value();
} else {
fileName = field.getName();
}
/**
* 如果表的名字 等于 成員變量的注解名字
*/
if (colmunName.equals(fileName)) {
colmunFiled = field;
break;
}
}
//找到了對應關系
if (colmunFiled != null) {
cacheMap.put(colmunName, colmunFiled);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
cursor.close();
}
}
@Override
public Long insert(T entity) {
Map<String, String> map = getValues(entity);
ContentValues values = getContentValues(map);
Long result = database.insert(tableName, null, values);
return result;
}
/**
* @param entity
* @param where
* @return
*/
@Override
public int update(T entity, T where) {
int result = -1;
Map values = getValues(entity);
/**
*講條件對象轉換map
*/
Map whereClause = getValues(where);
Condition condition = new Condition(whereClause);
ContentValues contentValues = getContentValues(values);
result = database.update(tableName, contentValues, condition.getWhereClause(), condition.getWhereArgs());
return result;
}
@Override
public int delete(T where) {
Map map = getValues(where);
Condition condition = new Condition(map);
/**
* id=1 數據
* id=? new String[]{ String.value(1)}
*/
int result = database.delete(tableName, condition.getWhereClause(), condition.getWhereArgs());
return result;
}
//查詢所有數據
@Override
public List<T> query(T where) {
return query(where, null, null, null);
}
@Override
public List<T> query(T where, String orderBy, Integer startIndex, Integer limit) {
Map map = getValues(where);
String limitString = null;
if (startIndex != null && limit != null) {
limitString = startIndex + " , " + limit;
}
Condition condition = new Condition(map);
Cursor cursor = database.query(tableName, null, condition.getWhereClause(), condition.getWhereArgs(),
null, null, orderBy, limitString);
List<T> result = getResult(cursor, where);
cursor.close();
return result;
}
private List<T> getResult(Cursor cursor, T where) {
ArrayList list = new ArrayList();
Object item;
while (cursor.moveToNext()) {
try {
item = where.getClass().newInstance();
/**
* 列名 name
* 成員變量名 Filed
*/
Iterator iterator = cacheMap.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry entry = (Map.Entry) iterator.next();
/**
* 得到列名
*/
String colomunName = (String) entry.getKey();
/**
* 然后以列名 拿到列名在游標的位置
*/
Integer colmunIndex = cursor.getColumnIndex(colomunName);
Field field = (Field) entry.getValue();
Class type = field.getType();
if (colmunIndex != -1) {
if (type == String.class) {
//反射方式賦值
field.set(item, cursor.getString(colmunIndex));
} else if (type == Double.class) {
field.set(item, cursor.getDouble(colmunIndex));
} else if (type == Integer.class) {
field.set(item, cursor.getInt(colmunIndex));
} else if (type == Long.class) {
field.set(item, cursor.getLong(colmunIndex));
} else if (type == Float.class) {
field.set(item, cursor.getFloat(colmunIndex));
} else if (type == byte[].class) {
field.set(item, cursor.getBlob(colmunIndex));
} else {
continue;
}
}
}
list.add(item);
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
return list;
}
/**
* 轉換成ContentValues
*
* @param map
* @return
*/
private ContentValues getContentValues(Map<String, String> map) {
ContentValues contentValues = new ContentValues();
Set keys = map.keySet();
Iterator<String> iterator = keys.iterator();
while (iterator.hasNext()) {
String key = iterator.next();
String value = map.get(key);
if (value != null) {
contentValues.put(key, value);
}
}
return contentValues;
}
private Map<String, String> getValues(T entity) {
HashMap<String, String> result = new HashMap<>();
Iterator<Field> fieldsIterator = cacheMap.values().iterator();
/**
* 循環遍歷 映射map的 Field
*/
while (fieldsIterator.hasNext()) {
Field columnToField = fieldsIterator.next();
String cacheKey = null;
String cacheValue = null;
if (columnToField.getAnnotation(DbFiled.class) != null) {
cacheKey = columnToField.getAnnotation(DbFiled.class).value();
} else {
cacheKey = columnToField.getName();
}
try {
if (null == columnToField.get(entity)) {
continue;
}
cacheValue = columnToField.get(entity).toString();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
result.put(cacheKey, cacheValue);
}
return result;
}
/**
* 創建表
*
* @return
*/
protected abstract String createTable();
/**
* 封裝修改語句
*/
class Condition {
/**
* 查詢條件
* name= ?&& password = ?
*/
private String whereClause;
private String[] whereArgs;
public Condition(Map<String, String> whereClause) {
ArrayList list = new ArrayList();
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append(" 1=1 ");
Set keys = whereClause.keySet();
Iterator iterator = keys.iterator();
while (iterator.hasNext()) {
String key = (String) iterator.next();
String value = whereClause.get(key);
if (value != null) {
/**
* 拼接條件查詢語句
* 1=1 and name =? and password = ?
*/
stringBuilder.append(" and " + key + " =?");
list.add(value);
}
}
this.whereClause = stringBuilder.toString();
this.whereArgs = (String[]) list.toArray(new String[list.size()]);
}
public String getWhereClause() {
return whereClause;
}
public void setWhereClause(String whereClause) {
this.whereClause = whereClause;
}
public String[] getWhereArgs() {
return whereArgs;
}
public void setWhereArgs(String[] whereArgs) {
this.whereArgs = whereArgs;
}
}
}
Bean：
@DbTable("tb_user")
public class User {
/**
* 數據字段支持注解和非注解
* 非注解：
* public Integer userId;
* 數據保存的字段名為 userId
* 注解：
* @DbFiled("teacher_id")
* public Integer userId;
* 數據保存的字段名為 teacher_id
*
* 要用Integer型 不要用int型，負責查詢不到
*/
public Integer userId;
@DbFiled("name")
public String name;
@DbFiled("password")
public String password;
public User(Integer userId, String name, String password) {
this.userId = userId;
this.name = name;
this.password = password;
}
public User() {
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"userId=" + userId +
", name='" + name + '\'' +
", password='" + password + '\'' +
'}';
}
}
@Target(ElementType.FIELD) //字段、枚舉的常量
@Retention(RetentionPolicy.RUNTIME) //注解會在class字節碼文件中存在，在運行時可以痛過反射獲取到
public @interface DbFiled {
String value();
}
@Target(ElementType.TYPE) //運用在接口、類枚舉、注解
@Retention(RetentionPolicy.RUNTIME) //注解會在class字節碼文件中存在，在運行時可以痛過反射獲取到
public @interface DbTable {
String value();
}
ConcreteDao：
public class UserDao extends BaseDao {
@Override
protected String createTable() {
return "create table if not exists tb_user(userId int,name varchar(20),password varchar(20))";
}
}
public class FileDao extends BaseDao {
@Override
protected String createTable() {
return "create table if not exists tb_file(time varchar(20),path varchar(20),description varchar(20))";
}
}
Client：
public class MainActivity extends AppCompatActivity {
private static final String TAG = "Main";
IBaseDao<User> baseDao;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
baseDao = BaseDaoFactory.getInstance().getDataHelper(UserDao.class, User.class);
}
}
3.增刪改查測試
Step1：增
public void save(View view) {
for (int i = 0; i < 20; i++) {
User user = new User(i, "teacher", "123456");
baseDao.insert(user);
}
/**
*寫入文件數據
*/
// BaseDao<FileBean> fileBeanBaseDao = BaseDaoFactory.getInstance().getDataHelper(FileDao.class, FileBean.class);
// fileBeanBaseDao.insert(new FileBean("2019-12-13", Environment.getExternalStorageDirectory() + "/kpioneer", "asdfg"));
}
執行queryAll 打印數據
02-06 17:51:06.151 4858-4858/com.haocai.haocaisqlite I/Main: 查詢到 20 條數據
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=0, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=1, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=2, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=3, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=4, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=5, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=6, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=7, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=8, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=9, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=10, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=11, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=12, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=13, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=14, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=15, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=16, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=17, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=18, name='teacher', password='123456'}
02-06 17:51:06.152 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=19, name='teacher', password='123456'}
Step2：改
public void update(View view) {
for (int i = 10; i < 20; i++) {
User where = new User();
where.setUserId(i);
User user = new User(i, "kpioneer", "8888");
//更新原name = teacher的數據
baseDao.update(user, where);
}
}
執行queryAll 打印數據
02-06 17:54:18.650 4858-4858/com.haocai.haocaisqlite I/Main: 查詢到 20 條數據
02-06 17:54:18.650 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=0, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=1, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=2, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=3, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=4, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=5, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=6, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=7, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=8, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=9, name='teacher', password='123456'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=10, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=11, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=12, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=13, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=14, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=15, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=16, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=17, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=18, name='kpioneer', password='8888'}
02-06 17:54:18.651 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=19, name='kpioneer', password='8888'}
Step3：查
public void query(View view) {
User where = new User();
where.setName("teacher");
List<User> list = baseDao.query(where);
Log.i(TAG, "查詢到 " + list.size() + " 條數據");
for (User user : list) {
Log.i(TAG, user.toString());
}
System.out.println("--------查詢某條數據-------");
User where2 = new User();
where2.setName("teacher");
where2.setUserId(5);
List<User> list2 = baseDao.query(where2);
Log.i(TAG, "查詢到 " + list2.size() + " 條數據");
}
打印數據
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: 查詢到 10 條數據
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=0, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=1, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=2, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=3, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=4, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=5, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=6, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=7, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=8, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=9, name='teacher', password='123456'}
02-06 17:58:49.530 4858-4858/com.haocai.haocaisqlite I/System.out: --------查詢某條數據-------
02-06 17:58:49.533 4858-4858/com.haocai.haocaisqlite I/Main: 查詢到 1 條數據
Step4：刪
public void delete(View view) {
User user = new User();
user.setName("teacher");
baseDao.delete(user);
}
執行queryAll 打印數據
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: 查詢到 10 條數據
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=10, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=11, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=12, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=13, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=14, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=15, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=16, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=17, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=18, name='kpioneer', password='8888'}
02-06 18:00:29.196 4858-4858/com.haocai.haocaisqlite I/Main: User{userId=19, name='kpioneer', password='8888'}
