直接保存对象到数据库Demo

package com.db4o; import android.app.Activity; import android.os.Bundle; public class TestDB4oActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); String DATABASE_PATH = this.getFilesDir().getAbsolutePath() + "/testdb4o"; System.out.println(DATABASE_PATH); //获取指定路径下数据库引用 ObjectContainer db = Db4oEmbedded.openFile(Db4oEmbedded.newConfiguration(), DATABASE_PATH); Student student1 = new Student("Ryan", 24); Student student2 = new Student("TangRen", 23); //插入 db.store(student1); db.store(student2); db.commit();//注意别忘了commit，否则数据更改不生效，机制类似一般的SQL数据库 //删除指定对象（删除全部则不设置条件） Student deleteOBJ = new Student(); deleteOBJ.setAge(23); ObjectSet<Student> resultObjectSet = db.queryByExample(deleteOBJ); while(resultObjectSet.hasNext()){ Student ss = resultObjectSet.next(); db.delete(ss); } db.commit(); //修改 Student updateOBJ = new Student(); updateOBJ.setName("Ryan"); ObjectSet<Student> objectSet = db.queryByExample(updateOBJ); if (objectSet.hasNext()) { Student stu = objectSet.next(); stu.setAge(25); db.store(stu); db.commit(); } //查询 Student queryOBJ = new Student(); //设置查询条件 // queryOBJ.setAge(23); ObjectSet<Student> result = db.queryByExample(queryOBJ); while(result.hasNext()){ Student st = result.next(); System.out.println("Name:"+st.getName()); System.out.println("Age:"+st.getAge()); } } }