java从mysql导出数据的具体实例_Java

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;
}
}

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java从mysql导出数据的具体实例

2019年07月22日 | 移动技术网IT编程 | 我要评论

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