DatabaseHelper.java
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package com.shunzhi.parent.util;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;
import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.support.ConnectionSource;
import com.j256.ormlite.table.TableUtils;
import com.shunzhi.parent.bean.ChildBean;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
/**
* Created by ToaHanDong on 2017/3/24.
*/
public class DatabaseHelper extends OrmLiteSqliteOpenHelper {
private static final String TABLE_NAME = "parent.db";
private Map<String, Dao> daos = new HashMap<String, Dao>();
private static DatabaseHelper instance;
public DatabaseHelper(Context context){
super(context,TABLE_NAME,null,1);
}
/*
创建数据库
*/
@Override
public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {
try {
TableUtils.createTableIfNotExists(connectionSource, ChildBean.class);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
try {
TableUtils.dropTable(connectionSource,ChildBean.class,true);
onCreate(database,connectionSource);
} catch (SQLException e) {
e.printStackTrace();
}
}
//删除数据库
public void deleteAll(){
try {
TableUtils.dropTable(connectionSource,ChildBean.class,true);
} catch (SQLException e) {
e.printStackTrace();
}
}
public static synchronized DatabaseHelper getHelper(Context context){
context=context.getApplicationContext();
if (null==instance){
synchronized (DatabaseHelper.class){
if (null==instance){
instance=new DatabaseHelper(context);
}
}
}
return instance;
}
public synchronized Dao getDao(Class clazz) throws SQLException {
Dao dao = null;
String className = clazz.getSimpleName();
if (daos.containsKey(className)) {
dao = daos.get(className);
}
if (dao == null) {
dao = super.getDao(clazz);
daos.put(className, dao);
}
return dao;
}
/**
* 释放资源
*/
@Override
public void close() {
super.close();
for (String key : daos.keySet())
{
Dao dao = daos.get(key);
dao = null;
}
}
}