xUtils系列之DbUtils-查询

来源：互联网发布：combox控件绑定数据库编辑：程序博客网时间：2024/06/05 08:30

其实DbUtils的代码已经很清楚了,所以举个例子来描述具体用法.

首先,建立一个实体类Person:

package com.example.entities;import com.lidroid.xutils.db.annotation.Column;import com.lidroid.xutils.db.annotation.Table;@Table(name="person")public class Person {private int id;@Column(column="name")private String name;@Column(column="hobby")private String hobby;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 getHobby() {return hobby;}public void setHobby(String hobby) {this.hobby = hobby;}@Overridepublic String toString(){return "[id="+id+" name="+name+" hobby="+hobby+"]";}}

新建一个MainActivity类,在onCreate函数里面可以这样用:

@Overrideprotected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);ViewUtils.inject(this);initWebView();DbUtils db = DbUtils.create(this);try {db.dropTable(Person.class);} catch (DbException e1) {// TODO Auto-generated catch blocke1.printStackTrace();}String[] names={"zhao","qian","sun","li","zhou","wu","zhen","wang"};String[] hobbys={"pingpong","pingpong","pingpong","football","football","basketball","basketball","basketball"};List<Person> list = new ArrayList<Person>();for(int i=0;i<8;++i){Person p = new Person();p.setName(names[i]);p.setHobby(hobbys[i]);list.add(p);}try {db.saveAll(list);db.findAll(Child.class);db.findAll(Selector.from(Child.class).where("id", ">", 2));db.findById(Child.class, 1);db.findFirst(Child.class);db.findFirst(Selector.from(Child.class).where("id", ">", 2));db.findDbModelAll(DbModelSelector.from(Child.class).groupBy("hobby").having(WhereBuilder.b("id", ">", 2)));db.findDbModelFirst(DbModelSelector.from(Child.class).groupBy("hobby").having(WhereBuilder.b("id", ">", 2)));Cursor c = db.execQuery(new SqlInfo("select * from child;"));//findDbModelFirst和findDbModelAll相当是对execQuery做了再次封装,//返回的DbModel中,封装了通过列名获取value的方法,如:String getString(String columnName)等等.DbModel model = db.findDbModelFirst(new SqlInfo("select * from child;")); //采取原生sql语句,可以做多表查询操作List<DbModel> modellist = db.findDbModelAll(new SqlInfo("select * from child;"));} catch (DbException e) {// TODO Auto-generated catch blocke.printStackTrace();}}

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