xUtils框架之数据库使用

xUtils是基于Afinal开发的目前功能比较完善的一个Android开源框架。这个框架里有网络模块,图片模块,注解模块,数据库操作模块等, 今天说下如何用xUtils来操作数据库.

1.先在app的build.gradle中添加依赖 compile 'org.xutils:xutils:3.3.36'

2.新建User实体类

/**
 * @table 表名
 */
@Table(name = "t_user")
public class User {


    /**
     * @colume 这个注解是将实体类的字段名和数据库字段名进行映射
     * id 主键,
     * autoGen 是否自动增长
     */
    @Column(name = "id",isId = true,autoGen = true)
    private int id;
    
    @Column(name = "name")
    private String name;
    
    @Column(name = "age")
    private int age;

    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 int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }
}

3.新建一个Application在onCreate中进行初始化

/**
 * Created by Administrator on 2018/3/31.
 * 此处需要初始化,不然会报错
 */

public class MyApplication extends Application{

    @Override
    public void onCreate() {
        super.onCreate();
        x.Ext.init(this);

    }
}

4.创建数据库管理类

/**
 * Created by Administrator on 2018/3/22.
 * 创建数据库管理类
 */

public class DBManager {


    private static final String TAG = DBManager.class.getSimpleName();
    public static DBManager dbManager;


    public static DBManager getDbManager(){
        if(dbManager == null){
            dbManager = new DBManager();
        }
        return dbManager;
    }

    private DBManager(){

    }


    public DbManager getConfig(){
        DbManager.DaoConfig daoConfig = new DbManager.DaoConfig()
                .setDbName("user.db")
                .setDbVersion(1)
                .setAllowTransaction(true)//开启实务
                .setDbOpenListener(new DbManager.DbOpenListener() {
                    @Override
                    public void onDbOpened(DbManager dbManager) {
          

                    }
                })
                .setDbUpgradeListener(new DbManager.DbUpgradeListener() {
                    @Override
                    public void onUpgrade(DbManager dbManager, int i, int i1) {
                  
                    }
                })
                .setTableCreateListener(new DbManager.TableCreateListener() {
                    @Override
                    public void onTableCreated(DbManager dbManager, TableEntity tableEntity) {
                       
                    }
                });
        return x.getDb(daoConfig);
    }



}

4.UserDao类,增删改查

public class UserDao {

    private static DbManager dbManager;

    static {
        dbManager = DBManager.getDbManager().getConfig();
    }


    /**
     * 增加一条用户数据
     * @param user
     */
    public static void add(User user){
        try {
            dbManager.save(user);
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

    public static void delete(User user){
        try {
            //直接删除
            dbManager.delete(user);

            //通过条件删除,删除id 为1的用户
            WhereBuilder whereBuilder = WhereBuilder.b();
            whereBuilder.and("id","=",1);
            dbManager.delete(User.class,whereBuilder);

            //通过条件删除,删除id 为<10的用户 或者 name为tom的用户
            WhereBuilder whereBuilder2 = WhereBuilder.b();
            whereBuilder.and("id","<",10).or("name","=","tom");
            dbManager.delete(User.class,whereBuilder2);

            //通过条件删除,删除id 为<10的用户 并且 name 中间用t的用户
            WhereBuilder whereBuilder3 = WhereBuilder.b();
            whereBuilder.and("id","<",10).and("name","like","%t%");
            dbManager.delete(User.class,whereBuilder3);

            //自定义SQL语句删除
            Cursor cursor = dbManager.execQuery("DELETE  FORM t_user WHERE id = 1");
            while(cursor.moveToNext()){

            }

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


    public static void update(User user){

        try {
            //通过user的set方法改变值之后,保存即可更新
            dbManager.saveOrUpdate(user);

            //通过条件更新,将id为1的姓名进行修改
            //KeyValue 用数据库的字段作为key 将值做为字段的值
            WhereBuilder whereBuilder = WhereBuilder.b();
            whereBuilder.and("id","=",1);
            KeyValue keyValue = new KeyValue("name","michael");
            dbManager.update(User.class,whereBuilder,keyValue);
        } catch (DbException e) {
            e.printStackTrace();
        }
    }


    public static void find(){

        try {
            //查询所有的User
            List userList = dbManager.findAll(User.class);

            //查询id = 1的用户
            List userList2 = dbManager.selector(User.class).where("id","=",1).findAll();

            //原生SQL查询
            Cursor cursor = dbManager.execQuery("SELECT * FORM t_user WHERE id = 1");
            while(cursor.moveToNext()){

            }

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

这是xUtils最常用的操作方法了,感觉还是比原生的SQLite使用方便很多,xUtils还有很多功能大家可以去摸索下,比如一对多,多对多等复杂的表关系如何操作。