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java从mysql导出数据的具体实例

  • 时间:2022-10-09 19:15 编辑: 来源: 阅读:
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摘要:java从mysql导出数据的具体实例
[u]复制代码[/u] 代码如下:
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);        } 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();     }    }   }   public static void Exp(int startid) {    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, 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;    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);     for(int i=1;i<=10000;i++)     {      add(Conn,"testTitle"+i+"-"+System.currentTimeMillis());     }    } 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();     }    }   }   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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