package com.sun.mysql;

import java.io.DataInput;

import java.io.DataOutput;

import java.io.IOException;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Iterator;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.io.Writable;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.Reducer;

import org.apache.hadoop.mapreduce.lib.db.DBConfiguration;

import org.apache.hadoop.mapreduce.lib.db.DBOutputFormat;

import org.apache.hadoop.mapreduce.lib.db.DBWritable;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;

/**

 * 将mapreduce的结果数据写入mysql中

 * @author asheng

 */

public class WriteDataToMysql {

/**

     * 重写DBWritable

     * @author asheng

     * TblsWritable需要向mysql中写入数据

     */

    public static class TblsWritable implements Writable, DBWritable 

    {  

            String tbl_name;  

            String tbl_type;  

            public TblsWritable() 

            {  

            

            }  

            public TblsWritable(String tbl_name,String tab_type) 

            {  

            this.tbl_name = tbl_name;

            this.tbl_type = tab_type;

            }  

            @Override  

            public void write(PreparedStatement statement) throws SQLException 

            {

                    statement.setString(1, this.tbl_name);  

                    statement.setString(2, this.tbl_type);  

            }  

            @Override  

            public void readFields(ResultSet resultSet) throws SQLException 

            {  

                    this.tbl_name = resultSet.getString(1);  

                    this.tbl_type = resultSet.getString(2);  

            }  

            @Override  

            public void write(DataOutput out) throws IOException 

            {  

                    out.writeUTF(this.tbl_name);

                    out.writeUTF(this.tbl_type);

            }  

            @Override  

            public void readFields(DataInput in) throws IOException 

            {  

                    this.tbl_name = in.readUTF();  

                    this.tbl_type = in.readUTF();  

            }  

            public String toString() 

            {  

                return new String(this.tbl_name + " " + this.tbl_type);  

            }  

    } 

    public static class ConnMysqlMapper extends Mapper<LongWritable,Text,Text,Text>

    //TblsRecord是自定义的类型，也就是上面重写的DBWritable类

   {  

        public void map(LongWritable key,Text value,Context context)throws IOException,InterruptedException 

        {  

        //<首字母偏移量,该行内容>接收进来，然后处理value，将abc和x作为map的输出

        //key对于本程序没有太大的意义，没有使用

        String name = value.toString().split(" ")[0];

        String type = value.toString().split(" ")[1];

                context.write(new Text(name),new Text(type));  

        }  

   }  

    public static class ConnMysqlReducer extends Reducer<Text,Text,TblsWritable,TblsWritable> 

    {  

        public void reduce(Text key,Iterable<Text> values,Context context)throws IOException,

                                                                                                                InterruptedException 

        {  

        //接收到的key value对即为要输入数据库的字段，所以在reduce中：

        //wirte的第一个参数，类型是自定义类型TblsWritable，利用key和value将其组合成TblsWritable，

                                                                                                                    然后等待写入数据库

        //wirte的第二个参数，wirte的第一个参数已经涵盖了要输出的类型，所以第二个类型没有用，设为null

        for(Iterator<Text> itr = values.iterator();itr.hasNext();) 

                 {  

                     context.write(new TblsWritable(key.toString(),itr.next().toString()),null); 

                 }  

        }  

    }  

    public static void main(String args[]) throws IOException, InterruptedException, ClassNotFoundException

    {

        Configuration conf = new Configuration(); 

        DBConfiguration.configureDB(conf, "com.mysql.jdbc.Driver","jdbc:mysql://127.0.0.1:3306/mapreduce_test","root", "root");    

        Job job = new Job(conf,"test mysql connection");  

        job.setJarByClass(ReadDataFromMysql.class);  

          

        job.setMapperClass(ConnMysqlMapper.class);  

        job.setReducerClass(ConnMysqlReducer.class);  

          

        job.setOutputKeyClass(Text.class);  

        job.setOutputValueClass(Text.class); 

        

        job.setInputFormatClass(TextInputFormat.class);  

        job.setOutputFormatClass(DBOutputFormat.class);

        FileInputFormat.addInputPath(job, new Path(args[0]));

        

        DBOutputFormat.setOutput(job, "lxw_tabls", "TBL_NAME","TBL_TYPE");

        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }

}

//执行输入参数为/home/asheng/hadoop/in/test3.txt

//test3.txt中的内容为

/*

abc x

def y

chd z

*/

//即将abc x分别做为TBL_NAME,和TBL_TYPE插入数据库中

//输出结果在mysql数据库中查看

//select * from lxw_tabls;

//发现新增三行

/*

abc x

def y

chd z

*/