SQLite 封装

这里是在 application.yaml 中来引进对 SQLite 的封装

java 复制代码

spring:
  datasource:
    url: jdbc:sqlite:./data/meta.db
    username:
    password:
    driver-class-name: org.sqlite.JDBC


mybatis:
  mapper-locations: classpath:mapper/**Mapper.xml

先进行建表操作:

使用一个接口类和对应的 xml 就可以进行对数据库的操作

然后对增删查进行封装

完整代码:

SQliteMapper:

java 复制代码

package com.example.mq.mqserver.mapper;

import com.example.mq.mqserver.core.Binding;
import com.example.mq.mqserver.core.Exchange;
import com.example.mq.mqserver.core.MSGQueue;

import java.util.List;

@Mapper //数据持久层
public interface SQLiteMapper {
    // 建表
    void createExchangeTable();
    void createQueueTable();
    void createBindingTable();

    // 增删查
    int insertExchange(Exchange exchange);
    int deleteExchange(String exchangeName);
    List<Exchange> selectAllExchange();

    int insertQueue(MSGQueue queue);
    int deleteQueue(String queueName);
    List<MSGQueue> selectAllQueue();

    int insertBinding(Binding binding);
    int deleteBinding(Binding binding);
    List<Binding> selectAllBinding();
}

SQLiteMapper.xml:

java 复制代码

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mq.mqserver.mapper.SQLiteMapper">
    <update id="createExchangeTable">
        create table if not exists exchange (name varchar(50) primary key, durable boolean, type int);
    </update>

    <update id="createQueueTable">
        create table if not exists queue(name varchar(50) primary key, durable boolean);
    </update>

    <update id="createBindingTable">
        create table if not exists binding(exchangename varchar(50), queuename varchar(50), durable boolean, bindingkey varchar(50));
    </update>

    <insert id="insertExchange">
        insert into exchange values(#{name}, #{durable}, #{type});
    </insert>

    <delete id="deleteExchange">
        delete from exchange where name = #{exchangeName};
    </delete>
    
    <select id="selectAllExchange" resultType="com.example.mq.mqserver.core.Exchange">
        select * from exchange;
    </select>
    
    <insert id="insertQueue">
        insert into queue values(#{name}, #{durable}); 
    </insert>
    
    <delete id="deleteQueue">
        delete form queue where name = #{queueName};
    </delete>
    
    <select id="selectAllQueue" resultType="com.example.mq.mqserver.core.MSGQueue">
        select * from queue;
    </select>
    
    <insert id="insertBinding">
        insert into binding values(#{exchangeName}, #{queueName}, #{durable}, #{bindingKey});
    </insert>
    
    <delete id="deleteBinding">
        delete from binding where exchangename = #{exchangeName} and queueName = #{queueName};
    </delete>
    
    <select id="selectAllBinding" resultType="com.example.mq.mqserver.core.Binding">
        select * from binding;
    </select>

    
</mapper>

然后我们创建一个类来对整合上述的数据库操作

先在 mqserver 中创建一个 datacenter 包, 这个包用来进行所有数据的管理

然后在包里创建一个 DataBaseManager 的类进行数据库操作的整合

DataBaseManager

checkDBExists() 查找数据库是不是存在

createTable() 之前构造好的方法

java 复制代码

    public boolean checkDBExists(){
        File file = new File("./data/meta.db");
        if(file.exists()){
            return true;
        }
        return false;
    }

    private void createTable(){
        sqLiteMapper.createExchangeTable();
        sqLiteMapper.createQueueTable();
        sqLiteMapper.createBindingTable();
    }

init() 对数据库进行初始化

java 复制代码

// 针对数据库进行初始化
    // 有 data 文件夹的话就不用创建
    // 没有就进行创建
    public void init(){
        if(!checkDBExists()){
            // 创建文件夹
            File dataDir = new File("./data");
            dataDir.mkdirs();
            // 创建数据表
            createTable();
            System.out.println("[DataBaseManager] 数据库初始化完成");
        }else {
            System.out.println("[DatBaseManager] 数据库已经存在");
        }

    }

然后是增删查:

这里把整个类全部放上来

java 复制代码

public class DataBaseManager {
    @Autowired
    SQLiteMapper sqLiteMapper;

    // 针对数据库进行初始化
    // 有 data 文件夹的话就不用创建
    // 没有就进行创建
    public void init(){
        if(!checkDBExists()){
            // 创建文件夹
            File dataDir = new File("./data");
            dataDir.mkdirs();
            // 创建数据表
            createTable();
            System.out.println("[DataBaseManager] 数据库初始化完成");
        }else {
            System.out.println("[DatBaseManager] 数据库已经存在");
        }

    }

    public boolean checkDBExists(){
        File file = new File("./data/meta.db");
        if(file.exists()){
            return true;
        }
        return false;
    }

    private void createTable(){
        sqLiteMapper.createExchangeTable();
        sqLiteMapper.createQueueTable();
        sqLiteMapper.createBindingTable();
    }

    public void deleteDB(){
        // 先删除里面的文件
        File file = new File("./data/meta.db");
        boolean ret = file.delete();
        if(ret){
            System.out.println("[DataBaseManager] 删除数据库文件成功!");
        }else {
            System.out.println("[DataBaseManager] 删除数据库文件失败!");
        }
        // 再删除文件夹
        File dataDir = new File("./data");
        ret = dataDir.delete();
        if(ret){
            System.out.println("[DataBaseManager] 删除数据库目录成功");
        }else {
            System.out.println("[DataBaseManager] 删除数据库目录失败");
        }
    }

    // 交换机操作
    public int insertExchange(Exchange exchange){
        return sqLiteMapper.insertExchange(exchange);
    }

    public int deleteExchange(String stingName){
        return sqLiteMapper.deleteExchange(stingName);
    }

    public List<Exchange> selectAllExchanges(){
        return sqLiteMapper.selectAllExchange();
    }

    // 队列操作
    public int insertQueue(MSGQueue queue){
        return sqLiteMapper.insertQueue(queue);
    }

    public int deleteQueue(String queueName){
        return sqLiteMapper.deleteQueue(queueName);
    }

    public List<MSGQueue> selectAllQueue(){
        return sqLiteMapper.selectAllQueue();
    }

    // 队列操作
    public int insertBinding(Binding binding){
        return sqLiteMapper.insertBinding(binding);
    }

    public int deleteBinding(Binding binding){
        return sqLiteMapper.deleteBinding(binding);
    }

    public List<Binding> selectAllBinding(){
        return sqLiteMapper.selectAllBinding();
    }

}

消息队列项目(2)

SQLite 封装

DataBaseManager