Java 之 批量从mysql导入Redis

一、pom

从插入redis数据需要转成JSON => 需要jackson的三个包！

java操作redis => 使用Jedis

<dependencies>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.6</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.38</version>
    </dependency>
<!-- java拿到List<Object> => 转成JSON -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.10.0</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.10.0</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.10.0</version>
    </dependency>
    <!-- redis -->
    <!-- https://mvnrepository.com/artifact/redis.clients/jedis -->
    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>3.1.0</version>
    </dependency>
  </dependencies>

二、目录

三、配置

mybatis.cfg.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC
        "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <typeAlias type="com.njbdqn.mor.entity.SalrsOrder" alias="so"></typeAlias>
    </typeAliases>
    <environments default="cm">
        <environment id="cm">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://192.168.56.111:3306/sales_source"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/so.xml"></mapper>
    </mappers>
</configuration>

mapper/so.xml

<?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.njbdqn.mor.dao.SalesOrderDao">
    <select id="findAll" resultType="so">
    SELECT order_number AS orderNumber,
            customer_number AS customerNumber,
            product_code AS productCode,
            order_date AS orderDate,
            entry_date AS entryDate,
            order_amount AS orderAmount FROM sales_order
    </select>
</mapper>

四、代码

实体类：

public class SalesOrder {
    private int orderNumber;
    private int customerNumber;
    private int productCode;
    private Date orderDate;
    private Date entryDate;
    private int orderAmount ;

dao层：

public interface SalesOrderDao {
    List<SalesOrder> findAll();
}

Test层：

public static String tucketNo(int i){
        // 此方法如果String值特别大会出现负数
        // hadoop默认的hashpartitioner中为了解决这个问题，使用与运算：(key.hashCode() & Integer.MAX_VALUE) % numReduceTasks;
        return (i+"").hashCode()%100000+"";
    }

    public static void main(String[] args) throws Exception {
        Reader read = Resources.getResourceAsReader("mybatis.cfg.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(read);
        SqlSession session = factory.openSession();
        SalesOrderDao sod = session.getMapper(SalesOrderDao.class);
        List<SalesOrder> all = sod.findAll();
        // 转化成json，在redis默认第0个hashmap中，salesorder这个key中存所有记录
        ObjectMapper om = new ObjectMapper();
        Jedis jedis = new Jedis("192.168.56.111",6379);
        for (SalesOrder so :all){ // 存JSON格式的String
            jedis.lpush("salesorder",om.writeValueAsString(so));
        }
        jedis.close();
        session.close();

五、验证Redis中数据

192.168.56.111:6379> LLEN salesorder
(integer) 100000
192.168.56.111:6379> LINDEX salesorder 100
"{\"orderNumber\":99900,\"customerNumber\":2,\"productCode\":3,\"orderDate\":1531929600000,\"entryDate\":1531929600000,\"orderAmount\":1454}"