android数据库操作

package cn.hackcoder.beautyreader.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

/**
 * Created by hackcoder on 15-1-25.
 */
public class DataBaseHelper extends SQLiteOpenHelper {
    private static final String dbName = "sample.db";
    private static int dbVersion = 1;

    public DataBaseHelper(Context context) {
        super(context,dbName,null,dbVersion);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        Log.d("===========","数据库初始化");
        //建表
        String sql = "create table if not exists tb_article(id integer primary key autoincrement,title varchar(50),content TEXT,url varchar(50),page integer)";
        db.execSQL(sql);
    }

    /**
     *
     * @param db
     * @param oldVersion
     * @param newVersion
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

package cn.hackcoder.beautyreader.service;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import java.util.ArrayList;
import java.util.List;

import cn.hackcoder.beautyreader.db.DataBaseHelper;
import cn.hackcoder.beautyreader.model.Article;

/**
 * Created by hackcoder on 15-1-25.
 */
public class ArticleService {

    private DataBaseHelper dataBaseHelper;
    private SQLiteDatabase readableDatabase;
    private SQLiteDatabase writableDatabase;

    public ArticleService(Context context) {
        dataBaseHelper = new DataBaseHelper(context);
    }

    public void add(Article article) {
        String sql = "insert into tb_article(id,title,content,url,page) values(?,?,?,?,?)";
        getReadableDatabase().execSQL(sql, new Object[]{null, article.getTitle(), article.getContent(), article.getUrl(), article.getPage()});
    }

    public void delete(int id) {
        String sql = "delete from tb_article where id =?";
        getReadableDatabase().execSQL(sql, new Object[]{id});
    }

    public void deleteAll() {
        String sql = "delete from tb_article";
        getReadableDatabase().execSQL(sql,null);
    }
    public void update(Article article) {
        String sql = "update tb_article set title=?,content=?,url=?,page = ? where id =?";
        getReadableDatabase().execSQL(sql, new Object[]{article.getTitle(), article.getContent(), article.getUrl(), article.getPage(), article.getId()});
    }

    public void updateContentOfUrl(String url,String content){
        String sql = "update tb_article set content=? where url =?";
        getReadableDatabase().execSQL(sql, new Object[]{content,url});
    }
    public Article find(int id) {
        Article article = new Article();
        String sql = "select id,title,content,url,page from tb_article where id = ?";
        Cursor cursor = getReadableDatabase().rawQuery(sql, new String[]{String.valueOf(id)});
        if (cursor.moveToNext()) {
            article.setId(id);
            article.setTitle(cursor.getString(cursor.getColumnIndex("title")));
            article.setContent(cursor.getString(cursor.getColumnIndex("content")));
            article.setUrl(cursor.getString(cursor.getColumnIndex("url")));
            article.setPage(cursor.getInt(cursor.getColumnIndex("page")));
            cursor.close();
            return article;
        }
        cursor.close();
        return null;
    }

    public List<Article> findByUrl(String url) {
        List<Article> articles = new ArrayList<Article>();
        String sql = "select id,title,content,url,page from tb_article where url = ?";
        Cursor cursor = getReadableDatabase().rawQuery(sql, new String[]{url});
        while (cursor.moveToNext()) {
            Article article = new Article();
            article.setId(cursor.getInt(cursor.getColumnIndex("id")));
            article.setTitle(cursor.getString(cursor.getColumnIndex("title")));
            article.setContent(cursor.getString(cursor.getColumnIndex("content")));
            article.setUrl(cursor.getString(cursor.getColumnIndex("url")));
            article.setPage(cursor.getInt(cursor.getColumnIndex("page")));
            articles.add(article);
        }
        cursor.close();
        return articles;
    }
    public int getCountOfPage(int page){
        String sql = "select count(*) from tb_article where page = ?";
        Cursor cursor = getReadableDatabase().rawQuery(sql, new String[]{String.valueOf(page)});
        cursor.moveToFirst();
        int count = cursor.getInt(0);
        cursor.close();
        return count;
    }

    public List<Article> getArticlesOfPage(int curPage){
        List<Article> articles = new ArrayList<Article>();
        String sql = "select id,title,content,url,page from tb_article where page = ?";
        Cursor cursor = getReadableDatabase().rawQuery(sql,new String[]{String.valueOf(curPage)});
        while(cursor.moveToNext()){
            Article article = new Article();
            article.setId(cursor.getInt(cursor.getColumnIndex("id")));
            article.setTitle(cursor.getString(cursor.getColumnIndex("title")));
            article.setContent(cursor.getString(cursor.getColumnIndex("content")));
            article.setUrl(cursor.getString(cursor.getColumnIndex("url")));
            article.setPage(cursor.getInt(cursor.getColumnIndex("page")));
            articles.add(article);
        }
        cursor.close();
        return articles;
    }
    public int countOfSum() {
        String sql = "select count(*) from tb_article";
        Cursor cursor = getReadableDatabase().rawQuery(sql, null);
        cursor.moveToFirst();
        int count = cursor.getInt(0);
        cursor.close();
        return count;
    }

    public List<Article> getArticles(int start, int pageSize) {
        List<Article> articles = new ArrayList<Article>();
        String sql = "select id,title,content,url,page from tb_article limit ?,?";
        Cursor cursor = getReadableDatabase().rawQuery(sql,new String[]{String.valueOf(start),String.valueOf(pageSize)});
        while(cursor.moveToNext()){
            Article article = new Article();
            article.setId(cursor.getInt(cursor.getColumnIndex("id")));
            article.setTitle(cursor.getString(cursor.getColumnIndex("title")));
            article.setContent(cursor.getString(cursor.getColumnIndex("content")));
            article.setUrl(cursor.getString(cursor.getColumnIndex("url")));
            article.setPage(cursor.getInt(cursor.getColumnIndex("page")));
            articles.add(article);
        }
        cursor.close();
        return articles;
    }

    public void closeDB() {
        if (readableDatabase != null && readableDatabase.isOpen()) {
            readableDatabase.close();
        }
        if (writableDatabase != null && writableDatabase.isOpen()) {
            writableDatabase.close();
        }
    }

    public SQLiteDatabase getReadableDatabase() {
        return dataBaseHelper.getReadableDatabase();
    }

    public SQLiteDatabase getWritableDatabase() {
        return dataBaseHelper.getWritableDatabase();
    }
}