Android官方ORM数据库Room技术解决方案：@Embedded内嵌对象（二）

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Android Room支持数据库表Java对象通过注解符@Embedded内嵌一个Java对象。这样就像过去的ORM数据库一样，比如构造一个名为Info的Java对象，作为一个成员变量添加到User里面：

package zhangphil.demo;

import android.arch.persistence.room.ColumnInfo;
import android.arch.persistence.room.Embedded;
import android.arch.persistence.room.Entity;
import android.arch.persistence.room.PrimaryKey;

/**
 * Created by Phil on 2017/11/22.
 */

@Entity(tableName = "user_table")
public class User {
    @PrimaryKey(autoGenerate = true)
    public int userId;

    @ColumnInfo(name = "userName")
    public String name;

    @ColumnInfo(name = "userAge")
    public int age;

    @ColumnInfo(name = "updateTime")
    public long updateTime;

    @Embedded
    public Info info;
}

package zhangphil.demo;

import android.arch.persistence.room.ColumnInfo;
import android.arch.persistence.room.Entity;
import android.arch.persistence.room.PrimaryKey;

/**
 * Created by Phil on 2017/11/23.
 */

@Entity(tableName = "info_table")
public class Info {
    @PrimaryKey(autoGenerate = true)
    public int infoId;

    @ColumnInfo(name = "blog")
    public String blog;

    @ColumnInfo(name = "content")
    public String content;
}

package zhangphil.demo;

import android.arch.persistence.room.Room;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private String TAG = "输出";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        new Thread(new Runnable() {
            @Override
            public void run() {
                databaseOperation();
            }
        }).start();
    }

    private void databaseOperation() {
        UserDatabase mUserDatabase = Room.databaseBuilder(getApplicationContext(), UserDatabase.class, "users").build();
        UserDao mUserDao = mUserDatabase.getUserDao();

        //写数据库
        writeUserDatabase(mUserDao, "zhangphil", 18);
        readDatabase(mUserDao);

        //关闭数据库
        mUserDatabase.close();
    }

    private void readDatabase(UserDao dao) {
        Log.d(TAG, "读数据库...");
        List<User> users = dao.getAllUsers();
        for (User u : users) {
            Log.d(TAG, u.userId + "," + u.name + "," + u.age + ","+u.info.blog+","+u.info.content);
        }
        Log.d(TAG, "读数据库完毕.");
    }

    private void writeUserDatabase(UserDao dao, String name, int age) {
        Info info = new Info();
        info.blog = "http://blog.csdn.net/zhangphil";
        info.content = "Android";

        User user = new User();
        user.name = name;
        user.age = age;
        user.updateTime = System.currentTimeMillis();

        user.info = info;

        dao.insertUser(user);
    }
}

代码运行结果，logcat输出：

11-24 09:20:00.716 30805-30851/zhangphil.demo D/输出: 读数据库...
11-24 09:20:00.723 30805-30851/zhangphil.demo D/输出: 1,zhangphil,18,http://blog.csdn.net/zhangphil,Android
11-24 09:20:00.723 30805-30851/zhangphil.demo D/输出: 读数据库完毕.

Android官方ORM数据库Room技术解决方案：@Embedded内嵌对象（二）

标签：support   解决   xtend   date   zhang   content   方案   detail   rri   

原文地址：http://blog.csdn.net/zhangphil/article/details/78621009