Java-将Oracle中某个表的数据导出成数据文件

　　在做数据开发或者ETL工作中，经常会遇到需要在客户端将Oracle数据库中的某些表的数据导出，提供给其他人员使用的情况。

     下面介绍我之前实施的一种方法：（该方法不是最好的办法，但是可以勉强使用，仅供参考）

实现逻辑：

1、编写Java程序（DBToFile.java），读取配置文件中的数据库连接信息，将表中的数据查询出来，并生成文件；

2、通过shell脚本(run-KF00001.sh、run-KF00002.sh)设置Java程序中需要的环境变量信息，并执行java程序；

3、通过启动脚本(run-day.sh)，依次执行第2步的多个shell脚本。

一、编写java程序(DBToFile.java)

import java.io.File;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import java.util.Properties;
import java.util.Iterator;
import java.util.Map.Entry;

public class DBToFile {
    public final static int PREPARE_OK = 0;
    public final static int RET_CONF_ERROR = 10;
    public final static int RET_ENV_ERROR = 15;
    public final static int RET_RUNTIME_ERROR = 5;
    public final static String DBTF_SQL = "DBTF_SQL";
    public final static String DBTF_OUTPUT_DIR = "DBTF_OUTPUT_DIR";
    public final static String DBTF_OUTPUT_FILE = "DBTF_OUTPUT_FILE";
    public final static String DBTF_OUTPUT = "DBTF_OUTPUT";
    public final static String JDBC_CLASS_NAME = "oracle.jdbc.driver.OracleDriver";
    public final static String CONFIG_FILE = "DBToFile.conf";
    public final static char SEPARATOR = 0x01;
    //
    private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
    //

    public static void main(String[] args) {
        File outputFile = null;
        BufferedWriter bw = null;
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        //
        StringBuffer sb = null;
        int rowCount = 0;
        long tt = 0L;

        Properties props = new Properties();
        int ret = loadConf(props);
        if (PREPARE_OK != ret) {
            System.exit(ret);
        }
        ret = loadEnv(props);
        if (PREPARE_OK != ret) {
            System.exit(ret);
        }
        showProperties(props);
        //data transfer
        try {
            tt = System.currentTimeMillis();
            outputFile = new File(props.getProperty(DBTF_OUTPUT) + ".avl");
            bw = new BufferedWriter(new FileWriter(outputFile));
            conn = getConn(props);
            conn.createStatement();
            stmt = conn.createStatement();
            rs = stmt.executeQuery(props.getProperty(DBTF_SQL));
            int count = rs.getMetaData().getColumnCount();
            String v = null;
            while (rs.next()) {
                sb = new StringBuffer();
                for (int i = 1; i <= count; i++) {
                    v = rs.getString(i);
                    if (null == v) {
                        v = "";
                    } else {
                        v = v.replaceAll("\r|\n", " ").trim();
                    }
                    sb.append(v);
                    if (i < count) {
                        sb.append(SEPARATOR);
                    }
                }
                bw.write(sb.toString());
                bw.newLine();
                rowCount++;
            }
            bw.flush();
            tt = System.currentTimeMillis() - tt;
            writeCheckFile(props.getProperty(DBTF_OUTPUT), props.getProperty(DBTF_OUTPUT_FILE), rowCount, outputFile.length());
            log("Output " + rowCount + " rows, " + outputFile.length() + " bytes, within " + tt + " ms.");
        } catch (IOException ioe) {
            ioe.printStackTrace();
            log("Output File Error");
            System.exit(RET_RUNTIME_ERROR);
        } catch (ClassNotFoundException cnfe) {
            cnfe.printStackTrace();
            log("Java CLASSPATH Error");
            System.exit(RET_RUNTIME_ERROR);
        } catch (SQLException sqle) {
            sqle.printStackTrace();
            log("DB Error");
            System.exit(RET_RUNTIME_ERROR);
        } finally {
            CloseWriter(bw);
            closeConn(conn);
        }
    }

    private static void writeCheckFile(String n, String nn, int c, long s) {
        try {
            FileWriter writer = new FileWriter(n  + ".chk", false);
                    writer.write(nn + "," + c + "," + s);
                    writer.close();
        } catch (IOException ioe) {
            ioe.printStackTrace();
            log("Output Check File Error");
        }
    }

    public static int loadEnv(Properties p) {
        Map<String, String> env = System.getenv();
        String v = env.get(DBTF_SQL);
        if (null == v || v.length() < 10) {
            log("Env DBTF_SQL Error");
            return RET_ENV_ERROR;
        } else {
            p.put(DBTF_SQL, v.trim());
        }
        String d = env.get(DBTF_OUTPUT_DIR);
        if (null == d || d.length() < 0) {
            log("Env DBTF_OUTPUT_DIR Error");
            return RET_ENV_ERROR;
        }
        File f = new File(d);
        if  (!f.exists()  || !f.isDirectory()) {
            log("Env DBTF_OUTPUT_DIR Error");
            return RET_ENV_ERROR;
        } else {
            String n = env.get(DBTF_OUTPUT_FILE);
            if  (null == n || n.length() < 1) {
                log("Env DBTF_OUTPUT_FILE Error");
                return RET_ENV_ERROR;
            } else {
                p.put(DBTF_OUTPUT_DIR, d.trim());
                p.put(DBTF_OUTPUT_FILE, n.trim());
                p.put(DBTF_OUTPUT, d.trim() + n.trim());
            }
        }
        return PREPARE_OK;
    }

    public static int loadConf(Properties p) {
        FileInputStream fis = null;
        String v;
        try {
            fis = new FileInputStream(CONFIG_FILE);
            p.load(fis);
            fis.close();
            v = p.getProperty("DB_URL");
            if (null == v || v.length() < 7) {
                log("Config File DB_URL Error");
                return RET_CONF_ERROR;
            }
            v = p.getProperty("DB_USERNAME");
            if (null == v || v.length() < 1) {
                log("Config File DB_USERNAME Error");
                return RET_CONF_ERROR;
            }
            v = p.getProperty("DB_PASSWORD");
            if (null == v || v.length() < 4) {
                log("Config File DB_PASSWORD Error");
                return RET_CONF_ERROR;
            }
            return PREPARE_OK;
        } catch (IOException ioe) {
            ioe.printStackTrace();
            log("Config File Error");
            return RET_CONF_ERROR;
        } finally {
            fis = null;
        }
    }

    public static void CloseWriter(BufferedWriter bw) {
        try {
            if (null != bw) {
                bw.close();
            }
        } catch(IOException e) {
            e.printStackTrace();
        }
    }

    public static Connection getConn(Properties p) throws ClassNotFoundException, SQLException {
        Class.forName(JDBC_CLASS_NAME);
        return DriverManager.getConnection(
                p.getProperty("DB_URL"),
                p.getProperty("DB_USERNAME"),
                p.getProperty("DB_PASSWORD"));
    }

    public static void closeConn(Connection conn) {
        try {
            if (conn != null)
                conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
            conn = null;
        }
    }

    private static void showProperties(Properties prop) {
        Iterator<Entry<Object, Object>> it = prop.entrySet().iterator();
        while (it.hasNext()) {
            Entry<Object, Object> entry = it.next();
            log(entry.getKey() + ":" + entry.getValue());
        }
    }

    private static void log(String s) {
        String d = sdf.format(new Date());
        System.out.println("<" + d + ">" + s);
    }

}

配置文件(DBToFile.conf)

DB_URL=jdbc:oracle:thin:@10.32.8.195:1521:orcl
DB_USERNAME=scott
DB_PASSWORD=scott
LOG_LEVEL=DEBUG

上面的Java程序，需要编译成class文件。

javac  DBToFile.java

二、编写运行shell脚本（run-KF00001.sh、run-KF00002.sh）

#!/bin/bash

export LANG="zh_CN.UTF-8"
export THE_LAST_DAY=`date -d yesterday +%Y%m%d`

export BIANHAO="KF00001"
export DBTF_SQL="select * from V_COMPLAINT_ALERT_INTERFACE where DATE_STAMP = "$THE_LAST_DAY
export DBTF_OUTPUT_DIR="/srv/BigData/bdkfsj/"$THE_LAST_DAY"/"

export DBTF_OUTPUT_FILE=$BIANHAO$THE_LAST_DAY
export JAVA_HOME=/srv/BigData/bdkfsj/jdk1.7.0_71
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/mylib/ojdbc6.jar

cd /srv/BigData/bdkfsj/bin/
java DBToFile
RET=$?
if [ $RET -ne 0 ]; then
    echo "Generate Data File FAILED, ERROR_ID = $RET"
    exit 2
else
    exit 0
fi

备注：1、运行shell脚本的服务器必须要安装jdk，并配置好环境变量；

2、CLASSPATH中需要使用odbc6.jar，这里我是放在 $JAVA_HOME/mylib/ 目录下。

三、编辑启动shell脚本（run-day.sh）

#!/bin/bash

export THE_NEW_DIR=/srv/BigData/bdkfsj/`date -d yesterday +%Y%m%d`
mkdir $THE_NEW_DIR

/srv/BigData/bdkfsj/bin/run-KF00001.sh
/srv/BigData/bdkfsj/bin/run-KF00002.sh
/srv/BigData/bdkfsj/bin/run-KF00003.sh
/srv/BigData/bdkfsj/bin/run-KF00004.sh
/srv/BigData/bdkfsj/bin/run-KF00005.sh
/srv/BigData/bdkfsj/bin/run-KF00006.sh
/srv/BigData/bdkfsj/bin/run-KF00007.sh
/srv/BigData/bdkfsj/bin/run-KF00008.sh
/srv/BigData/bdkfsj/bin/run-KF00009.sh
/srv/BigData/bdkfsj/bin/run-KF00010.sh

四、设置定时作业，每天凌晨1点钟执行导出任务。

crontab   -e

0 1 * * * sh /srv/BigData/bdkfsj/bin/run-day.sh 

5、预期结果

（1）每天会自动生成一个日期目录，这里是生成前一天的日期。（可以在run-day.sh中修改生成目录的日期）

（2）会自动导出的数据生成到avl文件中，同时生成chk文件(存放文件名，记录数，文件大小)用来做校验，防止数据确实不完整。

（3）可以通过vi命令查看导出的avl数据文件，文件是已^A作为分隔符。

（4）通过cat命令可以查看chk校验文件信息。

文件名为：KF0000120201115，记录数： 44, 文件大小：951