Android开发 ---ORMLite实现数据的增删改查，单例模式，Dao栈

效果图：

　

项目目录截图：

1、activity_main.xml

　　描述：

　　　　两行显示8个按钮

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:text="添加用户"
            android:onClick="addUser"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="查询用户"
            android:onClick="findUserList"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="删除用户"
            android:onClick="deleteUser"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="修改用户"
            android:onClick="updateUser"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
    </LinearLayout>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:text="添加部门"
            android:onClick="addDept"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="查询部门"
            android:onClick="findDeptList"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="添加员工"
            android:onClick="addEmp"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
        <Button
            android:text="查询员工"
            android:onClick="findEmpList"
            android:layout_width="match_parent"
            android:layout_weight="1"
            android:layout_height="wrap_content" />
    </LinearLayout>
</LinearLayout>

2、MainActivity.java

package com.nf.android_ormlite;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.nf.dao.DeptDao;
import com.nf.dao.EmpDao;
import com.nf.dao.UsersDao;
import com.nf.entity.TbDept;
import com.nf.entity.TbEmp;
import com.nf.entity.Users;

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

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    //添加用户操作
    //new一个Users将用户的编号、用户名、密码、日期封装起来交给UsersDao里的addUsers()方法进行添加用户的操作
    //添加成功返回结果并弹出提示
    public void addUser(View view) throws SQLException {
        boolean res=new UsersDao(this).addUsers(new Users(0,"abc","123123",new Date()));
        Toast.makeText(this, "添加用户结果是:"+res, Toast.LENGTH_SHORT).show();
    }
    //查询用户信息列表的操作
    //调用UsersDao里的getUserList()方法从数据库中获取到所有用户的信息，保存到list集合中
    public void findUserList(View view) throws SQLException {
        List<Users> users=new UsersDao(this).getUserList();
        //对list集合进行循环遍历，取出用户编号、用户名称、用户密码写入日志中
        for (Users user:users){
            Log.i("FindUserList:",user.get_id()+","+user.getUname()+","+user.getUpwd());
        }
    }
    //根据用户ID删除用户信息的操作
    //调用UserDao中的deleteUsers()方法传入一个用户ID，删除该ID对应的用户信息
    public void deleteUser(View view) throws SQLException {
        UsersDao dao=new UsersDao(this);
        Users user=dao.getUserById(3);
        boolean res=new UsersDao(this).deleteUsers(user);
        Toast.makeText(this, "删除用户结果是:"+res, Toast.LENGTH_SHORT).show();
    }
    //修改用户信息的操作
    //调用UserDao的updateUsers()方法将编号为2的用户的用户名称修改为Toms
    public void updateUser(View view) throws SQLException {

        UsersDao dao=new UsersDao(this);
        Users user=dao.getUserById(2);
        user.setUname("Toms");
        boolean res=dao.updateUsers(user);
        Toast.makeText(this, "修改用户结果是:"+res, Toast.LENGTH_SHORT).show();
    }
    //添加部门的操作
    //调用DeptDaod的addDept()方法添加一个学工部
    public void addDept(View view) throws SQLException {
        TbDept dept=new TbDept(0,"学工部");
        new DeptDao(this).addDept(dept);
        Toast.makeText(this, "添加部门成功", Toast.LENGTH_SHORT).show();
    }
    //查询部门的操作
    //调用DeptDao的findDeptList()方法从数据库中获取所有的部门信息放入list集合中
    public void findDeptList(View view) throws SQLException {中心
        List<TbDept> list=new DeptDao(this).findDeptList();
        //对list集合进行循环遍历，获取出部门编号、部门名称、该部门员工的人数
        for(TbDept dept:list){
            Log.i("DeptList:",dept.get_id()+","+dept.getDname()+","+dept.getEmps().size());
        }
    }
    //添加员工的操作
    //调用TbEmp()实体对象封装一名员工信息
    //再调用EmpDao中的addEmp()方法将员工信息添加到数据库
    //我们在员工表里再绑定他所在的部门
    public void addEmp(View view) throws SQLException {
        TbEmp emp=new TbEmp(0,"Kite",22,"男");
        //取出学术部
        TbDept dept=new DeptDao(this).getDeptById(2);
        //绑定员工和部门
        emp.setDept(dept);
        //保存员工
        new EmpDao(this).addEmp(emp);
        Toast.makeText(this, "添加员工成功", Toast.LENGTH_SHORT).show();
    }
    //查询员工信息的操作
    //调用EmpDao中的findempList()方法从数据库中查询出来放入list集合
    public void findEmpList(View v) throws Exception{
        List<TbEmp> emps=new EmpDao(this).findEmpList();
        //退list集合进行循环遍历，查询出所有员工的编号、姓名、部门名称
        for (TbEmp emp:emps){
            Log.i("EmpList:",emp.get_id()+","+emp.getEname()+","+emp.getDept().getDname());
        }
    }
}

3、dao/DeptDao.java

package com.nf.dao;
import android.content.Context;

import com.nf.entity.TbDept;
import com.nf.utils.DbHelper;

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

public class DeptDao {

    private DbHelper dbHelper;
    public DeptDao(Context context){
　　　　　//实例化DbHelper
        dbHelper=DbHelper.getInstance(context);
    }

    public boolean addDept(TbDept dept) throws SQLException {
　　　　　//通过dbHelper调用getDaos（）
        dbHelper.getDaos(TbDept.class).create(dept);
        return true;
    }

    public List findDeptList() throws SQLException {
        return dbHelper.getDaos(TbDept.class).queryForAll();
    }

    public TbDept getDeptById(int id) throws SQLException {
        return (TbDept) dbHelper.getDaos(TbDept.class).queryForId(id);
    }
}

4、dao/EmpDao.java

package com.nf.dao;
import android.content.Context;

import com.nf.entity.TbEmp;
import com.nf.utils.DbHelper;

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

/**
 * Created by Administrator on 2017/12/13.
 */

public class EmpDao {

    private DbHelper dbHelper;
    public EmpDao(Context context){
        dbHelper=DbHelper.getInstance(context);
    }

    public boolean addEmp(TbEmp emp) throws SQLException {
        dbHelper.getDaos(TbEmp.class).create(emp);
        return true;
    }

    public List findEmpList() throws SQLException {
        return dbHelper.getDaos(TbEmp.class).queryForAll();
    }
}

5、dao/UsersDao.java

package com.nf.dao;
import android.content.Context;

import com.nf.entity.Users;
import com.nf.utils.DbHelper;
import com.j256.ormlite.dao.Dao;
import com.j256.ormlite.stmt.DeleteBuilder;
import com.j256.ormlite.stmt.QueryBuilder;
import com.j256.ormlite.stmt.UpdateBuilder;

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

/**
 * Created by Administrator on 2017/12/13.
 */

public class UsersDao {

    private DbHelper dbHelper;
    private Dao dao;//DbHelper对象提供的一个对象持久化类
    public UsersDao(Context context){
        dbHelper=new DbHelper(context);
        try {
            dao=dbHelper.getDao(Users.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //添加一个用户
    public boolean addUsers(Users user) throws SQLException {
        dao.create(user);
        return true;
    }

    //修改一个用户
    public boolean updateUsers(Users user) throws SQLException {
        dao.update(user);
        return true;
    }

    //删除一个用户
    public boolean deleteUsers(Users user) throws SQLException {
        dao.delete(user);
        return true;
    }

    public Users getUserById(int id) throws SQLException {
        Users user=(Users) dao.queryForId(id);
        return user;
    }

    public List getUserList() throws SQLException {
        List list=dao.queryForAll();
        return list;
    }

    //==============批量操作=============//
    public boolean addUsers(List<Users> users) throws SQLException {
        dao.create(users);
        return true;
    }
    public boolean deleteUsers(List<Users> users) throws SQLException {
        dao.delete(users);
        return true;
    }

    //==============带条件修改删除查询=============//
    public boolean updateUsersByPwd(String query) throws SQLException {
        UpdateBuilder builder=dao.updateBuilder();
        builder.where().like("upwd",query);
        builder.updateColumnValue("upwd","123456");
        builder.update();
        return true;
    }

    public boolean deleteUsers(String name) throws SQLException {
        DeleteBuilder builder=dao.deleteBuilder();
        builder.where().eq("uname",name);
        builder.delete();
        return true;
    }
    public List findUserList(String name) throws SQLException {
        QueryBuilder builder=dao.queryBuilder();
        builder.where().like("uname","%"+name+"%");
        builder.orderBy("uintime",true);
        List list=builder.query();
        return list;
    }
}

6、entity/TbDept.java

package com.nf.entity;
import com.j256.ormlite.dao.ForeignCollection;
import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.field.ForeignCollectionField;
import com.j256.ormlite.table.DatabaseTable;

import java.io.Serializable;

@DatabaseTable(tableName = "tb_dept") //通过注解的方式设置部门表的表名
public class TbDept implements Serializable {

    @DatabaseField(generatedId = true)//设置部门编号 generatedId = true表示编号自动增长
    private int _id;
    @DatabaseField //默认设置
    private String dname;

    //一对多的关系
    @ForeignCollectionField(eager = false)
    private ForeignCollection<TbEmp> emps;

    public TbDept() {
    }

    public TbDept(int _id, String dname) {
        this._id = _id;
        this.dname = dname;
    }

    public int get_id() {
        return _id;
    }

    public void set_id(int _id) {
        this._id = _id;
    }

    public String getDname() {
        return dname;
    }

    public void setDname(String dname) {
        this.dname = dname;
    }

    public ForeignCollection<TbEmp> getEmps() {
        return emps;
    }

    public void setEmps(ForeignCollection<TbEmp> emps) {
        this.emps = emps;
    }
}

7、entity/TbEmp.java

package com.nf.entity;
import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.table.DatabaseTable;

import java.io.Serializable;
//指定表名称
@DatabaseTable(tableName = "tb_emp")
public class TbEmp implements Serializable {

    @DatabaseField(generatedId = true)
    private int _id;
    @DatabaseField
    private String ename;
    @DatabaseField
    private int eage;
    @DatabaseField
    private String esex;

    //多对一的关系
    @DatabaseField(columnName = "edno",foreign = true,foreignAutoRefresh = true,canBeNull = false)
    private TbDept dept;

    public TbEmp() {
    }

    public TbEmp(int _id, String ename, int eage, String esex) {
        this._id = _id;
        this.ename = ename;
        this.eage = eage;
        this.esex = esex;
    }

    public int get_id() {
        return _id;
    }

    public void set_id(int _id) {
        this._id = _id;
    }

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public int getEage() {
        return eage;
    }

    public void setEage(int eage) {
        this.eage = eage;
    }

    public String getEsex() {
        return esex;
    }

    public void setEsex(String esex) {
        this.esex = esex;
    }

    public TbDept getDept() {
        return dept;
    }

    public void setDept(TbDept dept) {
        this.dept = dept;
    }
}

8、entity/Users.java

package com.nf.entity;

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

import java.io.Serializable;
import java.util.Date;

/**
 * Created by Administrator on 2017/12/13.
 */
@DatabaseTable(tableName = "tb_users")
public class Users implements Serializable{
　　　//指定该字段为主键且自动增长
    @DatabaseField(generatedId = true)
    private int _id;
　　 //指定字段不能为空
    @DatabaseField(canBeNull = false)
    private String uname;
    @DatabaseField(canBeNull = false)
    private String upwd;
    @DatabaseField(dataType = DataType.DATE)
    private Date uintime;

    public Users() {
    }

    public Users(int _id, String uname, String upwd, Date uintime) {
        this._id = _id;
        this.uname = uname;
        this.upwd = upwd;
        this.uintime = uintime;
    }

    public int get_id() {
        return _id;
    }

    public void set_id(int _id) {
        this._id = _id;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public String getUpwd() {
        return upwd;
    }

    public void setUpwd(String upwd) {
        this.upwd = upwd;
    }

    public Date getUintime() {
        return uintime;
    }

    public void setUintime(Date uintime) {
        this.uintime = uintime;
    }
}

9、DbHelper.java

package com.nf.utils;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import android.widget.Toast;

import com.nf.entity.TbDept;
import com.nf.entity.TbEmp;
import com.nf.entity.Users;
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.util.Date;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
//构建一个DbHelper类继承OrmLiteSqliteOpenHelper 实现对数据库的操作
public class DbHelper extends OrmLiteSqliteOpenHelper {
    //定义数据库名称
    private static final String DATABASE_NAME="ormlite.db";
    //定义数据库的版本
    private static final int VERSION=3;
    //构造器，将上下文对象、数据库名称、工厂、版本信息初始化
    public DbHelper(Context context) {//用于通过注解+反射创建数据库表
        super(context, DATABASE_NAME, null, VERSION);//用于通过读取配置文件创建数据库表
    }
    private DbHelper(Context context, String databaseName, SQLiteDatabase.CursorFactory factory, int databaseVersion) {
        super(context, DATABASE_NAME, null, VERSION);
    }

    //第一次创建数据库时执行
    @Override
    public void onCreate(SQLiteDatabase database, ConnectionSource connectionSource) {
        try {
            //创建表Tb_users
            TableUtils.createTableIfNotExists(connectionSource, Users.class);
            //创建表Tb_dept
            TableUtils.createTableIfNotExists(connectionSource, TbDept.class);
            //创建表Tb_emp
            TableUtils.createTableIfNotExists(connectionSource, TbEmp.class);
        } catch (SQLException e) {
            e.printStackTrace();
        }

        //加入测试数据
        try {
            //调用Dao中的getDao()方法传入一个实体对象，实体对象里封装一个用户，通过create()方法，将这个用户初始化到tb_users数据表中
            Dao dao=getDao(Users.class);//创建一个Users类的Dao
            dao.create(new Users(0,"admins","admins",new Date()));
        } catch (SQLException e) {
            e.printStackTrace();
        }
        Log.i("create table","创建数据表成功");
    }

    @Override
    public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
        try {
            TableUtils.dropTable(connectionSource,Users.class,true);
            TableUtils.dropTable(connectionSource,TbEmp.class,true);
            TableUtils.dropTable(connectionSource,TbDept.class,true);
            onCreate(database,connectionSource);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //===================提供单例模式DbHelper对象提供服务=========================//
    private static DbHelper dbHelper;

    public static synchronized DbHelper getInstance(Context context){
        if(dbHelper==null){
            dbHelper=new DbHelper(context);
        }
        return dbHelper;
    }

    //==================构建一个Dao栈，统一管理Dao=======================//
    private Map<String,Dao> daos=new HashMap<String,Dao>();

    public Dao getDaos(Class cls) throws SQLException {
        String className=cls.getName();//获取类名
        if(!daos.containsKey(className)){
            daos.put(className,super.getDao(cls));
        }
        return daos.get(className);
    }

    //重写DbHelper的close方法
    @Override
    public void close() {
        super.close();
        Iterator it=daos.keySet().iterator();
        while(it.hasNext()){
            Dao dao=(Dao) it.next();
            dao=null;
        }
    }
}