数据采集之Web端导入DB数据到Hadoop HDFS

Love The Way You Lie 2022-09-29 04:10 3阅读 0赞

# 前言 #

接上一篇**[数据采集之Web端上传文件到Hadoop HDFS][Web_Hadoop HDFS]**，总共需求有3个，这篇记录如何通过Web端将MySQL表数据导入到HDFS中，主要是通过**Sqoop2**这个工具，之前已经写了一篇**[ Sqoop2 从MySQL导入数据到Hadoop HDFS][Sqoop2 _MySQL_Hadoop HDFS]**，不过那个是在命令行下操作的。

这回通过Java API的形式操作，其中还是有不少坑的。

# 环境 #

*  OS Debian 8.7
 *  Hadoop 2.6.5
 *  SpringBoot 1.5.1.RELEASE
 *  MySQL 5.7.17 Community Server
 *  Sqoop 1.99.7

# 项目依赖 #

废话不多说，直接先上**pom.xml**依赖文件。

<?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.infosys.sqoop</groupId>
        <artifactId>sqoop</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <name>sqoop</name>
    
        <packaging>jar</packaging>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.1.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <hadoop.version>2.6.5</hadoop.version>
            <sqoop.version>1.99.7</sqoop.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>3.1.0</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
    
            <dependency>
                <groupId>org.apache.sqoop</groupId>
                <artifactId>sqoop-client</artifactId>
                <version>${sqoop.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-log4j12</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            <dependency>
                <groupId>org.apache.derby</groupId>
                <artifactId>derby</artifactId>
                <version>10.10.2.0</version>
            </dependency>
    
    
            <dependency>
                <groupId>org.apache.hadoop</groupId>
                <artifactId>hadoop-client</artifactId>
                <version>${hadoop.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-log4j12</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            <dependency>
                <groupId>org.apache.hadoop</groupId>
                <artifactId>hadoop-common</artifactId>
                <version>${hadoop.version}</version>
                <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-log4j12</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
    
            <dependency>
                <groupId>org.apache.mrunit</groupId>
                <artifactId>mrunit</artifactId>
                <version>1.1.0</version>
                <classifier>hadoop2</classifier>
                <scope>test</scope>
            </dependency>
    
            <dependency>
                <groupId>org.apache.hadoop</groupId>
                <artifactId>hadoop-minicluster</artifactId>
                <version>${hadoop.version}</version>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
    
        <build>
            <finalName>${project.artifactId}</finalName>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-archetype-plugin</artifactId>
                    <version>2.2</version>
                </plugin>
    
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-resources-plugin</artifactId>
                    <configuration>
                        <encoding>UTF-8</encoding>
                    </configuration>
                </plugin>
    
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.1</version>
    
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                    </configuration>
                </plugin>
    
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    </project>

其中Springboot只是为了快速搭建web框架，然后就是使用到了**Hadoop Client**和**Sqoop**相关的Jar包。需要注意的是其中的**日志框架**，有好几个**slf4j**的实现，我们排除掉几个。

# 核心Sqoop #

这里只是演示，不是真实项目，所以就偷懒下，逻辑都写一起了。真实项目中必须要抽取，毕竟不只是支持一种数据库，而且一些配置选项是可以通过web端传入的。

package com.infosys.sqoop.controller;
    
    import com.infosys.sqoop.Driver;
    import com.infosys.sqoop.ToFormat;
    import org.apache.sqoop.client.SqoopClient;
    import org.apache.sqoop.client.SubmissionCallback;
    import org.apache.sqoop.model.*;
    import org.apache.sqoop.validation.Status;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import static com.infosys.sqoop.Constans.*;
    
    /** * 描述： * 公司：infosys(印孚瑟斯技术有限公司) * 作者：luhaoyuan <lusyoe@163.com> * 版本：1.0 * 创建日期：2017/3/12. */
    @RestController
    public class SqoopController { 
    
        private static final Logger log = LoggerFactory.getLogger(SqoopController.class);
    
    
        @PostMapping(value = "/mysql2HDFS")
        public String mysqlToHDFS() throws Exception {
    
            Driver.mkdir(new String[]{HDFS_OUTPUT});
    
            SqoopClient client = new SqoopClient(SQOOP_URL);
    
            configSourceLink(client);
    
            configDestLink(client);
    
            configJob(client);
    
            startJob(client);
    
            return "SUCCESS!";
        }
    
    
        private void startJob(SqoopClient client) throws InterruptedException {
    
            // 启动JOB并设置回调
            MSubmission submission = client.startJob(JOB_NAME, DEFAULT_SUBMISSION_CALLBACKS, 100);
    
            log.debug("Job Submission Status: " + submission.getStatus());
    
            log.debug("Hadoop job id: " + submission.getExternalJobId());
            log.debug("Job link: " + submission.getExternalLink());
    
            if(submission.getStatus().isFailure()) {
                log.error("Submission has failed: " + submission.getError().getErrorSummary());
                log.error("Corresponding error details: " + submission.getError().getErrorDetails());
            }
    
        }
    
    
        protected static final SubmissionCallback DEFAULT_SUBMISSION_CALLBACKS = new SubmissionCallback() {
            @Override
            public void submitted(MSubmission submission) {
                log.info("Submission submitted: " + submission);
            }
    
            @Override
            public void updated(MSubmission submission) {
                log.info("Submission updated: " + submission);
            }
    
            @Override
            public void finished(MSubmission submission) {
                log.info("Submission finished: " + submission);
            }
        };
    
    
    
        private void configJob(SqoopClient client) {
    
            MJob job = client.createJob(FROM_LINK_NAME, TO_LINK_NAME);
    
            job.setName(JOB_NAME);
    
            // 设置源 link 配置
            MFromConfig fromJobConfig = job.getFromJobConfig();
            fromJobConfig.getStringInput("fromJobConfig.schemaName")
                    .setValue(SOURCE_DB);
    
            fromJobConfig.getStringInput("fromJobConfig.tableName")
                    .setValue(SOURCE_TABLE);
    
    
            fromJobConfig.getStringInput("fromJobConfig.partitionColumn")
                    .setValue("id");
    
    
            // 设置目的 link 配置
            MToConfig toJobConfig = job.getToJobConfig();
    
    
            toJobConfig.getStringInput("toJobConfig.outputDirectory")
                    .setValue(HDFS_OUTPUT);
    
            toJobConfig.getEnumInput("toJobConfig.outputFormat").setValue(ToFormat.TEXT_FILE);
    
    
            client.saveJob(job);
        }
    
    
        /** * 配置目的链接 */
        private void configDestLink(SqoopClient client) {
            MLink link = client.createLink("hdfs-connector");
    
            link.setName(TO_LINK_NAME);
    
            MLinkConfig linkConfig = link.getConnectorLinkConfig();
    
            linkConfig.getStringInput("linkConfig.confDir")
                    .setValue("/home/hadoop/hadoop/etc/hadoop");
    
            Status status = client.saveLink(link);
    
            if (status.canProceed()) {
                log.debug("Created Link with Link Name : " + link.getName());
            } else {
                log.debug("Something went wrong creating the link");
            }
        }
    
    
        /** * 配置数据源链接 */
        private void configSourceLink(SqoopClient client) {
    
    
            MLink link = client.createLink("generic-jdbc-connector");
    
            link.setName(FROM_LINK_NAME);
    
            MLinkConfig linkConfig = link.getConnectorLinkConfig();
    
            // 配置link属性
            // 配置源连接
            linkConfig.getStringInput("linkConfig.connectionString")
                    .setValue(DB_SCHEMA);
    
            // 配置MySQL数据库驱动
            linkConfig.getStringInput("linkConfig.jdbcDriver")
                    .setValue("com.mysql.jdbc.Driver");
    
            // 配置数据连接用户和密码
            linkConfig.getStringInput("linkConfig.username")
                    .setValue(DB_USERNAME);
            linkConfig.getStringInput("linkConfig.password")
                    .setValue(DB_PASSWD);
    
            // mysql这里地方必须要注意了，如果不设置会报SQL语法错误，
            // 因为默认是使用"包裹数据库和表名的，这个mysql不支持
            linkConfig.getStringInput("dialect.identifierEnclose")
                    .setValue("");
    
            log.debug("source link conf = " + linkConfig.toString());
    
            Status status = client.saveLink(link);
    
            if (status.canProceed()) {
                log.debug("Created Link with Link Name : " + link.getName());
            } else {
                log.debug("Something went wrong creating the link");
            }
    
        }
    
    }

# Hadoop操作 #

Sqoop导入到HDFS的输出目录必须为空，否则会报错。所以这里可以操作**Hadoop Client**创建一个路径。

package com.infosys.sqoop;
    
    import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.FileSystem;
    import org.apache.hadoop.fs.Path;
    import org.apache.hadoop.mapred.IFile;
    import org.apache.hadoop.util.GenericOptionsParser;
    
    import java.io.IOException;
    
    import static com.infosys.sqoop.Constans.FS_DEFAULT_FS;
    import static com.infosys.sqoop.Constans.HDFS_HOST;
    
    /** * 描述： * 公司：infosys(印孚瑟斯技术有限公司) * 作者：luhaoyuan <lusyoe@163.com> * 版本：1.0 * 创建日期：2017/3/12. */
    public class Driver { 
    
    
        public static void mkdir(String[] args) throws IOException {
    
            Configuration conf = new Configuration();
    
            conf.set(FS_DEFAULT_FS, HDFS_HOST);
    
            GenericOptionsParser optionsParser = new GenericOptionsParser(conf, args);
    
            String[] remainingArgs = optionsParser.getRemainingArgs();
            if (remainingArgs.length < 1) {
                System.err.println("need a path");
                System.exit(2);
            }
    
            Path path = new Path(args[0]);
    
            FileSystem fs = FileSystem.get(conf);
    
            if (!fs.exists(path)) {
                fs.mkdirs(path);
            }
    
        }
    }

# 常量 #

最后是一些常量配置，也贴出来吧~

package com.infosys.sqoop;
    
    /** * 描述： * 公司：infosys(印孚瑟斯技术有限公司) * 作者：luhaoyuan <lusyoe@163.com> * 版本：1.0 * 创建日期：2017/3/12. */
    public final class Constans { 
    
        public static final String FS_DEFAULT_FS = "fs.defaultFS";
        public static final String HDFS_HOST = "hdfs://e5:9000";
    
        public static final String SQOOP_URL = "http://192.168.1.2:12000/sqoop/";
    
        // mysql db name
        public static final String SOURCE_DB = "hadoopguide";
    
        // table name
        public static final String SOURCE_TABLE = "widgets";
    
        public static final String HDFS_OUTPUT = "/sqoop";
    
        // job name
        public static final String JOB_NAME = "web-job";
    
        // from link name
        public static final String FROM_LINK_NAME = "web-link";
    
        // to link name
        public static final String TO_LINK_NAME = "web-hdfs";
    
    
        // DB url
        public static final String DB_SCHEMA = "jdbc:mysql://192.168.1.2:3306/hadoopguide?useSSL=false";
    
        public static final String DB_USERNAME = "root";
        public static final String DB_PASSWD = "lu123";
    }

# 后记 #

为了写这个都花了大半天时间了，其中的坑真的是蛮多的。一些配置又没有常量API提供，而且MapReduce Job又不好调试，这里下面再记录一下测试过程的一些错误。

java.lang.Throwable: 
    The statement was aborted because it would have caused a duplicate key 
    value in a unique or primary key constraint or unique index identified by 
    'FK_SQ_LNK_NAME_UNIQUE' defined on 'SQ_LINK'

这个我怀疑是没设置数据库字段为Null时的处理方式导致的，反正我是把某个字段为Null的设置了一个值，然后就没报错了。

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 
    You have an error in your SQL syntax; check the manual that corresponds 
    to your MySQL server version for the right syntax to use near 
    '"hadoopguide"."widgets"' at line 1

这个就是我上面说的**边界符**问题，在MySQL中不支持，必须要在配置**源链接**的时候设置一下：

linkConfig.getStringInput("dialect.identifierEnclose")
                    .setValue("");

其他的数据库就没有测试了，如果有测试过的朋友可以说说哈~

> 参考：  
> [http://sqoop.apache.org/docs/1.99.7/dev/ClientAPI.html][http_sqoop.apache.org_docs_1.99.7_dev_ClientAPI.html]

[Web_Hadoop HDFS]: http://blog.csdn.net/lusyoe/article/details/61413592
[Sqoop2 _MySQL_Hadoop HDFS]: http://blog.csdn.net/lusyoe/article/details/60478226
[http_sqoop.apache.org_docs_1.99.7_dev_ClientAPI.html]: http://sqoop.apache.org/docs/1.99.7/dev/ClientAPI.html