android——CRUD(在上一篇博客的基础上)

本文链接：https://blog.youkuaiyun.com/hjd_love_zzt/article/details/9157637

本文介绍了一个基于Android平台的SQLite数据库操作案例，包括Person类定义、PersonDao类实现增删改查功能及测试用例。演示了如何通过Java代码进行数据库交互。

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1、Person

package com.njupt.sqlite;

public class Person {

	private Integer id;
	private String name;
	private Integer balance;
	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 Integer getBalance() {
		return balance;
	}
	public void setBalance(Integer balance) {
		this.balance = balance;
	}
	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", balance=" + balance
				+ "]";
	}
	public Person(Integer id, String name, Integer balance) {
		super();
		this.id = id;
		this.name = name;
		this.balance = balance;
	}
	
	public Person() {
		super();
	}
	
	
	
}

2、PersonDao

package com.njupt.sqlite;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class PersonDao {

	private DBOpenHelper helper;
	
	public PersonDao(Context context){
		helper = new DBOpenHelper(context);
	}
	
	public void insert(Person p){
		SQLiteDatabase db = helper.getWritableDatabase();
		
		db.execSQL("insert into person1(name,balance) values(?,?)",new Object[]{p.getName(),p.getBalance()});
	    db.close();
	}
	
	public void delete(int id){
		 SQLiteDatabase db = helper.getWritableDatabase();
		    db.execSQL("delete from person1 where id = ?",new Object[]{id});
		    db.close();
	}
	
	
	public void update(Person p){
		SQLiteDatabase db = helper.getWritableDatabase();
		db.execSQL("update person1 set name = ? , balance = ? where id = ?", new Object[]{p.getName(),p.getBalance(),p.getId()});
		db.close();
	}
	
	public Person query(int id){
		SQLiteDatabase db = helper.getReadableDatabase();
		Cursor c = db.rawQuery("select name ,balance from person1 where id = ?", new String[]{id + ""});
		Person p = null;
		
		if(c.moveToNext()){
			String name = c.getString(0);
			int balance = c.getInt(1);
			
			p = new Person(id,name,balance);
		}
		
		
		return p;
	}
	   
	    		
	
}

3、DBTest

以下附上测试类

package com.njupt.sqlite;

import android.test.AndroidTestCase;

public class DBTest extends AndroidTestCase{

	public void test1(){
		DBOpenHelper helper = new DBOpenHelper(getContext());
		helper.getWritableDatabase();
		
	}
	
	public void testInsert(){
		PersonDao dao = new PersonDao(getContext());
		
		Person p = new Person(3,"章泽天",45000);
		
		dao.insert(p);
	}
	
	public void testDelete(){
		PersonDao dao = new PersonDao(getContext());
		
		int id = 1;
		dao.delete(id);
	}
	
	public void testUpdate(){
		PersonDao dao = new PersonDao(getContext());
		
		Person p = new Person(2,"lss",40000);
		
		dao.update(p);
		
	}
	
	
	public void testQuery(){
		PersonDao dao = new PersonDao(getContext());
		
		Person p = dao.query(3);
		
		System.out.println(p);
	}
}

4、最后我们可以在SQLiteExpert中看到相应的变化