ORMLite的使用

首先需要下载core和android两个jar

http://ormlite.com/releases/

然后拷贝到libs文件夹下并且添加为库

具体的使用看标程：

School.java

 package com.turtle920.ormlitedemo;

 import com.j256.ormlite.field.DatabaseField;
 import com.j256.ormlite.table.DatabaseTable;

 @DatabaseTable(tableName = "school")
 public class School {

     @DatabaseField(generatedId=true)
     private int id;

     @DatabaseField(columnName = "name")
     private String name;

     @DatabaseField
     private String location;

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getLocation() {
         return location;
     }

     public void setLocation(String location) {
         this.location = location;
     }
 }

以上通过注释符来用框架反射table和field，(generatedId=true)表示自增长

DBHelper.java

 package com.turtle920.ormlitedemo;

 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 java.sql.SQLException;

 public class DBHelper extends OrmLiteSqliteOpenHelper {

     private final static int DATABASE_VERSION = 1;
     Dao<School, Integer> mSchoolDao;
     private static final String DB_NAME = "orm";
     private static DBHelper mDbHelper;

     private DBHelper(Context context) {
         super(context, DB_NAME, null, DATABASE_VERSION);
     }

     public static DBHelper getInstance(Context context) {
         if (mDbHelper == null) {
             mDbHelper = new DBHelper(context);
         }
         return mDbHelper;
     }

     @Override
     public void onCreate(SQLiteDatabase arg0, ConnectionSource arg1) {
         try {
             TableUtils.createTableIfNotExists(connectionSource, School.class);
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }

     @Override
     public void onUpgrade(SQLiteDatabase arg0, ConnectionSource arg1, int arg2,
                           int arg3) {
     }

     public Dao<School, Integer> getSchoolDao() throws SQLException {
         if (mSchoolDao == null) {
             mSchoolDao = getDao(School.class);
         }
         return mSchoolDao;
     }

 }

这个类继承自OrmLiteSqliteOpenHelper.class继承自SqliteOpenHelper.class，相当于是增强版的

MainActivity.java

 package com.turtle920.ormlitedemo;

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.util.Log;

 import com.j256.ormlite.dao.Dao;

 import java.sql.SQLException;
 import java.util.List;

 public class MainActivity extends AppCompatActivity {

     private static final String TAG = "DaoDaoDao";
     DBHelper mDbHelper;
     Dao<School, Integer> mSchoolDao;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         mDbHelper = DBHelper.getInstance(this);
         try {
             mSchoolDao = mDbHelper.getSchoolDao();
         } catch (SQLException e) {
             Log.e(TAG, "constructor exception", e);
         }
         testDao();
     }

     private void testDao() {

         School school1 = new School();
         school1.setName("university");
         school1.setLocation("shanghai");

         School school2 = new School();
         school2.setName("middle school");
         school2.setLocation("hubei");

         School school3 = new School();
         school3.setName("CDQZ");
         school3.setLocation("CHENGDU");

         try {
             mSchoolDao.create(school1);
             mSchoolDao.create(school2);
             mSchoolDao.create(school3);
             //获取表中所有的student。
             Log.e(TAG,"************BEGIN*************");
             List<School> schools=mSchoolDao.queryForAll();
             Log.e(TAG, "before delete school1 size is:" + schools.size());
             for (int i = 0; i < schools.size(); i++) {
                 Log.e(TAG, schools.get(i).getId()+" "+schools.get(i).getName()+" "+schools.get(i).getLocation());
             }
             mSchoolDao.delete(school1);

             //schools=mSchoolDao.queryForAll();
             schools=mSchoolDao.queryForEq("id","3");
             Log.e(TAG, "after delete school1 list size is:"+schools.size());
             for (int i = 0; i < schools.size(); i++) {
                 Log.e(TAG, schools.get(i).getId()+" "+schools.get(i).getName()+" "+schools.get(i).getLocation());
             }

         } catch (SQLException e) {
             e.printStackTrace();
         }
     }

 }

其中一些操作：

 .queryForEq("id","3");//查询“id”=“3”的
 .queryForAll();//所有
 .delete(school1);//删除
 .deleteById(int id);//按id删
 .update(school);//更新
 .create(school);//插入

可以看到对数据库的访问被投影成了对对象的操作，相比直接用android给的api操作数据库要短平快的多。