sqlite

//创建数据库

public class sql extends SQLiteOpenHelper{





public sql(Context context) {
super(context, "shuju", null, 2);
// TODO Auto-generated constructor stub
}


@Override
public void onCreate(SQLiteDatabase db) {
//创建表
db.execSQL("create table stu (id integer primary key,name varchar(20),age int,sex varchar(10))");

}


@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
switch (newVersion) {
case 2:
db.execSQL("create table stu1 (id integer primary key,tname varchar(20),paw varchar(20),ban varchar(10))");
db.execSQL("insert into stu1(tname,paw,ban) values('张三','123456','1510A')");
db.execSQL("insert into stu1(tname,paw,ban) values('李四','456123','1510B')");
db.execSQL("insert into stu1(tname,paw,ban) values('王五','789456','1510C')");
break;
default:
break;
}
}


}

//创建操作类

public class sqldao {

sql sq;
Context cex;
private SQLiteDatabase sb;


public sqldao(Context cex) {
super();
this.sq =new sql(cex);
}
//添加
public void add(Sqlbean sd){
sb = sq.getWritableDatabase();
sb.execSQL("insert into stu(name,age,sex )values(?,?,?)", new Object[]{sd.getName(),sd.getAge(),sd.getSex()});
}
//修改
public void update(String name,int id){
sb = sq.getWritableDatabase();
sb.execSQL("update stu set name=? where id=?", new Object[]{name,id});
}
//删除
public void delete(String id){
sb = sq.getWritableDatabase();
sb.execSQL("delete from stu  where id=?", new Object[]{id});
}
public List<Sqlbean> select(){
List<Sqlbean> st=new ArrayList<Sqlbean>();
sb=sq.getReadableDatabase();
Cursor query = sb.rawQuery("select *from stu", null);
while (query.moveToNext()) {
Sqlbean sql=new Sqlbean(query.getInt(0), query.getString(1),query.getInt(2)+"", query.getString(3));
st.add(sql);
}
return st;}
//账户表
public List<String[]> select1(){
List<String[]> st=new ArrayList<String[]>();
sb=sq.getReadableDatabase();
Cursor query = sb.rawQuery("select *from stu1", null);
while (query.moveToNext()) {
String[] sql={query.getInt(0)+"", query.getString(1),query.getString(2), query.getString(3)};
st.add(sql);
}
return st;}

}

//在Studio中使用

//数据库Sqlite sq;//上下文Context context;private SQLiteDatabase db;public SqlDao(Context context) {    this.sq = new Sqlite(context);}//添加数据public void addJson(String json,String url){    db = sq.getWritableDatabase();    //添加前根据URL地址删除旧数据    db.execSQL("delete from jsonu where url=?",new String[]{url});    //删除后添加数据    db.execSQL("insert into jsonu(json,url) values(?,?)",new String[]{json,url});    //关闭    db.close();}//查询数据public  String select(String url){  db = sq.getReadableDatabase();    //将数据根据URL地址查询出来    Cursor query = db.rawQuery("select * from jsonu where url=?", new String[]{url});   //循环查找数据    while (query.moveToNext()){        //将数据查询出来返回        String json = query.getString(query.getColumnIndex("json"));        return json;    }    return null;}

//在NetWorkUrl里添加

SqlDao sq=new SqlDao(context);sq.addJson(s,path);