java从mysql导出数据的具体实例

2019-11-26 15:51:08

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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestDB {

public static void main(String[] args) {

//Test(); // 生成测试数据
//Exp();
Exp(0);
//System.out.println(readText("/opt/id.txt"));
}

/**
* 导出数据
*/
public static void Exp() {

Connection Conn=null;

   try {


    Class.forName("com.mysql.jdbc.Driver").newInstance();
    String jdbcUrl = "jdbc:mysql://127.0.0.1:3306/test?characterEncoding=GBK";
    //String jdbcUsername = "root";
    //String jdbcPassword = "mysql";
    Conn = DriverManager.getConnection(jdbcUrl, "root", "mysql");

    System.out.println("conn"+Conn);

    Exp(Conn);

   try {

    Class.forName("com.mysql.jdbc.Driver").newInstance();
    String jdbcUrl = "jdbc:mysql://127.0.0.1:3306/test?characterEncoding=GBK";
    String jdbcUsername = "root";
    String jdbcPassword = "mysql";
    Conn = DriverManager.getConnection(jdbcUrl, jdbcUsername, jdbcPassword);

    System.out.println("conn"+Conn);

    Exp(Conn,startid);

   } catch (SQLException e) {
    e.printStackTrace();
   }
   catch (InstantiationException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   } catch (ClassNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   finally
   {

    try {
     Conn.close();
    } catch (SQLException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }

}

/**
   * 导出从startid开始的数据
   * @param conn
   * @param start_id
   */
public static void Exp(Connection conn,int start_id) {

   int counter = 0;
   int startid=start_id;
   boolean flag = true;
   while (flag) {
    flag = false;
    String Sql = "SELECT * FROM t_test WHERE id>"
      + startid + " order by id asc LIMIT 50";

    System.out.println("sql===" + Sql);
    try {
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery(Sql);

      while (rs.next()) {
       flag = true;
       int id = rs.getInt("id");
       String title = rs.getString("title");
       startid = id ;

       counter++;

       writeContent(counter+"--id--"+id+"--title-"+title+"/r/n", "D://","log.txt",true);

       System.out.println("i="+counter+"--id--"+id+"--title-"+title);

      }
     rs.close();
     stmt.close();
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }

   writeContent(""+startid, "D://","id.txt",false);

}

/**
   * 导出一小时内的数据
   * @param conn
   */

public static void Exp(Connection conn) {

   int counter = 0;
   //一小时内的数据
   Long timestamp = System.currentTimeMillis() - (600 * 60 * 1000);
   boolean flag = true;
   while (flag) {
    flag = false;
    String Sql = "SELECT * FROM t_test WHERE createTime>"
      + timestamp + " LIMIT 50";

    System.out.println("sql===" + Sql);
    try {
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery(Sql);
     while (rs.next()) {
      flag = true;
      int id = rs.getInt("id");
      String title = rs.getString("title");
      Long lastmodifytime = rs.getLong("createTime");
      timestamp = lastmodifytime;

      counter++;

      System.out.println("i="+counter+"--id--"+id+"--title-"+title);

     }
     rs.close();
     stmt.close();
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }

}

public static void Test() {

Connection Conn=null;

public static void add(Connection conn,String title)
   {
      PreparedStatement pstmt = null;
   String insert_sql = "insert into t_test(title,createTime) values (?,?)";

   System.out.println("sql="+insert_sql);
   try {
    pstmt = conn.prepareStatement(insert_sql);
    pstmt.setString(1,title);
    pstmt.setLong(2,System.currentTimeMillis());
    int ret = pstmt.executeUpdate();

   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   finally{
    try {
     pstmt.close();
    } catch (SQLException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }

     }

/**
   * 写入内容到文件
   *
   * @param number
   * @param filename
   * @return
   */
public static boolean writeContent(String c, String dirname,String filename,boolean isAppend) {

   File f=new File(dirname);
   if (!f.exists())
   {
     f.mkdirs();
   }

   try {
    FileOutputStream fos = new FileOutputStream( dirname+File.separator+filename,isAppend);
    OutputStreamWriter writer = new OutputStreamWriter(fos);
    writer.write(c);
    writer.close();
    fos.close();
   } catch (IOException e) {
    e.printStackTrace();
    return false;
   }
   return true;
}

/**
   * 从文件读取内容
   *
   * @param filename
   * @return
   */
public static String readText(String filename) {
   String content = "";
   try {
    File file = new File(filename);
    if (file.exists()) {
     FileReader fr = new FileReader(file);
     BufferedReader br = new BufferedReader(fr);
     String str = "";
     String newline = "";
     while ((str = br.readLine()) != null) {
      content += newline + str;
      newline = "/n";
     }
     br.close();
     fr.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
   return content;
}
}