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Android SQLite数据库增删改查操作的案例分析

2019年07月24日  | 移动技术网IT编程  | 我要评论

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person实体类

复制代码 代码如下:

package com.ljq.domain;


public class person {
    private integer id;
    private string name;
    private string phone;

    public person() {
        super();
    }

    public person(string name, string phone) {
        super();
        this.name = name;
        this.phone = phone;
    }

    public person(integer id, string name, string phone) {
        super();
        this.id = id;
        this.name = name;
        this.phone = phone;
    }

    public integer getid() {
        return id;
    }

    public void setid(integer id) {
        this.id = id;
    }

    public string getname() {
        return name;
    }

    public void setname(string name) {
        this.name = name;
    }

    public string getphone() {
        return phone;
    }

    public void setphone(string phone) {
        this.phone = phone;
    }

}


dbopenhelper数据库关联类
复制代码 代码如下:

package com.ljq.db;

import android.content.context;
import android.database.sqlite.sqlitedatabase;
import android.database.sqlite.sqliteopenhelper;

public class dbopenhelper extends sqliteopenhelper {
    // 类没有实例化,是不能用作父类构造器的参数,必须声明为静态
    private static final string dbname = "ljq.db";
    private static final int version = 1;

    // 第三个参数cursorfactory指定在执行查询时获得一个游标实例的工厂类,
    // 设置为null,代表使用系统默认的工厂类
    public dbopenhelper(context context) {
        super(context, dbname, null, version);
    }

    @override
    public void oncreate(sqlitedatabase db) {
        db.execsql("create table person (id integer primary key autoincrement, name varchar(20), phone varchar(20))");
    }

    @override
    public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {
        // 注：生产环境上不能做删除操作
        db.execsql("drop table if exists person");
        oncreate(db);
    }
}


personservice业务类
复制代码 代码如下:

package com.ljq.db;

import java.util.arraylist;
import java.util.list;

import android.content.context;
import android.database.cursor;

import com.ljq.domain.person;

public class personservice {
    private dbopenhelper dbopenhelper = null;

    /**
     * 构造函数
     *
     * 调用getwritabledatabase()或getreadabledatabase()方法后，会缓存sqlitedatabase实例；
     * 因为这里是手机应用程序，一般只有一个用户访问数据库，所以建议不关闭数据库，保持连接状态。
     * getwritabledatabase()，getreadabledatabase的区别是当数据库写满时，调用前者会报错，调用后者不会，
     * 所以如果不是更新数据库的话，最好调用后者来获得数据库连接。
     *
     * 对于熟悉sql语句的程序员最好使用exesql(),rawquery(),因为比较直观明了
     *
     * @param context
     */
    public personservice(context context){
        dbopenhelper = new dbopenhelper(context);
    }

    public void save(person person){
        dbopenhelper.getwritabledatabase().execsql("insert into person(name, phone) values (?, ?)",
                new object[]{person.getname(), person.getphone()});
    }

    public void update(person person){
        dbopenhelper.getwritabledatabase().execsql("update person set name=?, phone=? where id=?",
                new object[]{person.getname(), person.getphone(), person.getid()});
    }

    public void delete(integer... ids){
        if(ids.length>0){
            stringbuffer sb = new stringbuffer();
            for(integer id : ids){
                sb.append("?").append(",");
            }
            sb.deletecharat(sb.length() - 1);
            dbopenhelper.getwritabledatabase().execsql("delete from person where id in ("+sb+")", (object[])ids);
        }
    }

    public person find(integer id){
        cursor cursor = dbopenhelper.getreadabledatabase().rawquery("select id, name, phone from person where id=?",
                new string[]{string.valueof(id)});
        if(cursor.movetonext()){
            int personid = cursor.getint(0);
            string name = cursor.getstring(1);
            string phone = cursor.getstring(2);
            return new person(personid, name, phone);
        }
        return null;
    }

    public long getcount(){
        cursor cursor = dbopenhelper.getreadabledatabase().query("person",
                new string[]{"count(*)"}, null,null,null,null,null);
        if(cursor.movetonext()){
            return cursor.getlong(0);
        }
        return 0;
    }

    /**
     * 分页
     *
     * @param startresult 偏移量，默认从0开始
     * @param maxresult 每页显示的条数
     * @return
     */
    public list<person> getscrolldata(int startresult, int maxresult){
        list<person> persons = new arraylist<person>();
        //cursor cursor = dbopenhelper.getreadabledatabase().query("person", new string[]{"id, name, phone"},
        //        "name like ?", new string[]{"%ljq%"}, null, null, "id desc", "1,2");
        cursor cursor = dbopenhelper.getreadabledatabase().rawquery("select * from person limit ?,?",
                new string[]{string.valueof(startresult), string.valueof(maxresult)});
        while(cursor.movetonext()) {
            int personid = cursor.getint(0);
            string name = cursor.getstring(1);
            string phone = cursor.getstring(2);
            persons.add(new person(personid, name, phone));
        }
        return persons;
    }

   

}


personservicetest测试类
复制代码 代码如下:

package com.ljq.test;

import java.util.list;

import com.ljq.db.personservice;
import com.ljq.domain.person;

import android.test.androidtestcase;
import android.util.log;

public class personservicetest extends androidtestcase{
    private final string tag = "personservicetest";

    public void testsave() throws exception{
        personservice personservice = new personservice(this.getcontext());
        personservice.save(new person("zhangsan1", "059188893343"));
        personservice.save(new person("zhangsan2", "059188893343"));
        personservice.save(new person("zhangsan3", "059188893343"));
        personservice.save(new person("zhangsan4", "059188893343"));
        personservice.save(new person("zhangsan5", "059188893343"));
    }

    public void testupdate() throws exception{
        personservice personservice = new personservice(this.getcontext());
        person person = personservice.find(1);
        person.setname("linjiqin");
        personservice.update(person);
    }

    public void testfind() throws exception{
        personservice personservice = new personservice(this.getcontext());
        person person = personservice.find(1);
        log.i(tag, person.getname());
    }

    public void testlist() throws exception{
        personservice personservice = new personservice(this.getcontext());
        list<person> persons = personservice.getscrolldata(0, 10);
        for(person person : persons){
            log.i(tag, person.getid() + " : " + person.getname());
        }
    }

    public void testcount() throws exception{
        personservice personservice = new personservice(this.getcontext());
        log.i(tag, string.valueof(personservice.getcount()));
    }

    public void testdelete() throws exception{
        personservice personservice = new personservice(this.getcontext());
        personservice.delete(1);
    }

    public void testdeletemore() throws exception{
        personservice personservice = new personservice(this.getcontext());
        personservice.delete(new integer[]{2, 5, 6});
    }
}


运行结果

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