Spark读取CSV数据

我们在日常的SparkSql开发中，会常常接处到CSV数据的拉取，通常出现在，数据库select结果导出或者是特定的处理结果

pom如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.wy</groupId>
    <artifactId>zoukao2</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>2.11.8</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.11</artifactId>
            <version>2.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.11</artifactId>
            <version>2.0.2</version>
        </dependency>
    </dependencies>


    <build>
        <pluginManagement>
            <plugins>
                <!-- 编译scala的插件 -->
                <plugin>
                    <groupId>net.alchim31.maven</groupId>
                    <artifactId>scala-maven-plugin</artifactId>
                    <version>3.2.2</version>
                </plugin>
                <!-- 编译java的插件 -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.5.1</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>scala-compile-first</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>scala-test-compile</id>
                        <phase>process-test-resources</phase>
                        <goals>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>


            <!-- 打jar插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.4.3</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

拉取方式如下

第一种方式用SparkSql

package com.sparksql

import org.apache.spark.sql.SparkSession

object DataFrameFromCSV {
    
    
  def main(args: Array[String]): Unit = {
    
    
    val spark: SparkSession = SparkSession
      .builder()
      .master("local")
      .appName("DataFrameFromStuctType")
      .getOrCreate()

    //如果是最普通的数据以英文逗号分隔的CSV文件
	//我们可以直接用spark.read.csv("C:\\Users\\Desktop\\people.csv")拉取
	//但是很多时候我们需要其他的设置，因此我用另一种方式给大家拉取
    val peopleDF = spark.read.format("csv")
      .option("sep", ",")//数据的分隔符
      .option("header", "true")//首行是否字段元数据
      .load("C:\\Users\\Desktop\\people.csv")

    peopleDF.createOrReplaceTempView("people")

    spark.sql("select * from people").show()
    spark.stop()
  }
}

第二种方式用SparkCore，但是一般没事干不会这样拉，后期处理就是在给自己挖坑

	val t = new SparkConf().setMaster("local").setAppName("T")
    val context = new SparkContext(t)
    val value = context.textFile("C:\\Users\\123.csv")
    value.foreach(println(_))