当前位置导航:炫浪网>>网络学院>>编程开发>>Oracle教程

JDBC存取ORACLE大型数据对象LOB几种情况的示范类


  import java.io.*;
  import java.util.*;
  import java.sql.*;
  
  public class LobPros
  {
  
    /**
    * ORACLE驱动程序
    */
    private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
  
    /**
    * ORACLE连接用URL
    */
    private static final String URL = "jdbc:oracle:thin:@test2000:1521:orac";
  
    /**
    * 用户名
    */
    private static final String USER = "user";
  
    /**
    * 密码
    */
    private static final String PASSWORD = "pswd";
  
    /**
    * 数据库连接
    */
    private static Connection conn = null;
  
    /**
    * SQL语句对象
    */
    private static Statement stmt = null;
  
    /**
    * @roseuid 3EDA089E02BC
    */
    public LobPros()
    {
  
    }
  
    /**
    * 往数据库中插入一个新的CLOB对象
    *
    * @param infile - 数据文件
    * @throws java.lang.Exception
    * @roseuid 3EDA04A902BC
    */
    public static void clobInsert(String infile) throws Exception
    {
      /* 设定不自动提交 */
      boolean defaultCommit = conn.getAutoCommit();
      conn.setAutoCommit(false);
  
      try {
        /* 插入一个空的CLOB对象 */
        stmt.executeUpdate("INSERT INTO TEST_CLOB VALUES ('111', EMPTY_CLOB())");
        /* 查询此CLOB对象并锁定 */
        ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
        while (rs.next()) {
          /* 取出此CLOB对象 */
          oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
          /* 向CLOB对象中写入数据 */
          BufferedWriter out = new BufferedWriter(clob.getCharacterOutputStream());
          BufferedReader in = new BufferedReader(new FileReader(infile));
          int c;
          while ((c=in.read())!=-1) {
            out.write(c);
          }
          in.close();
          out.close();
        }
        /* 正式提交 */
        conn.commit();
      } catch (Exception ex) {
        /* 出错回滚 */
        conn.rollback();
        throw ex;
      }
  
      /* 恢复原提交状态 */
      conn.setAutoCommit(defaultCommit);
    }
  
    /**
    * 修改CLOB对象(是在原CLOB对象基础上进行覆盖式的修改)
    *
    * @param infile - 数据文件
    * @throws java.lang.Exception
    * @roseuid 3EDA04B60367
    */
    public static void clobModify(String infile) throws Exception
    {
      /* 设定不自动提交 */
      boolean defaultCommit = conn.getAutoCommit();
      conn.setAutoCommit(false);
  
      try {
        /* 查询CLOB对象并锁定 */
        ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
        while (rs.next()) {
          /* 获取此CLOB对象 */
          oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
          /* 进行覆盖式修改 */
          BufferedWriter out = new BufferedWriter(clob.getCharacterOutputStream());
          BufferedReader in = new BufferedReader(new FileReader(infile));
          int c;
          while ((c=in.read())!=-1) {
            out.write(c);
          }
          in.close();
          out.close();
        }
        /* 正式提交 */
        conn.commit();
      } catch (Exception ex) {
        /* 出错回滚 */
        conn.rollback();
        throw ex;
      }
  
      /* 恢复原提交状态 */
      conn.setAutoCommit(defaultCommit);
    }
  
    /**
    * 替换CLOB对象(将原CLOB对象清除,换成一个全新的CLOB对象)
    *
    * @param infile - 数据文件
    * @throws java.lang.Exception
    * @roseuid 3EDA04BF01E1
    */
    public static void clobReplace(String infile) throws Exception
    {
      /* 设定不自动提交 */
      boolean defaultCommit = conn.getAutoCommit();
      conn.setAutoCommit(false);
  
      try {
        /* 清空原CLOB对象 */
        stmt.executeUpdate("UPDATE TEST_CLOB SET CLOBCOL=EMPTY_CLOB() WHERE ID='111'");
        /* 查询CLOB对象并锁定 */
        ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
        while (rs.next()) {
          /* 获取此CLOB对象 */
          oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
          /* 更新数据 */
          BufferedWriter out = new BufferedWriter(clob.getCharacterOutputStream());
          BufferedReader in = new BufferedReader(new FileReader(infile));
          int c;
          while ((c=in.read())!=-1) {
            out.write(c);
          }
          in.close();
          out.close();
        }
        /* 正式提交 */
        conn.commit();
      } catch (Exception ex) {
        /* 出错回滚 */
        conn.rollback();
        throw ex;
      }
  
      /* 恢复原提交状态 */
      conn.setAutoCommit(defaultCommit);
    }
  
    /**
    * CLOB对象读取
    *
    * @param outfile - 输出文件名
    * @throws java.lang.Exception
    * @roseuid 3EDA04D80116
    */
    public static void clobRead(String outfile) throws Exception
    {
      /* 设定不自动提交 */
      boolean defaultCommit = conn.getAutoCommit();
      conn.setAutoCommit(false);
  
      try {
        /* 查询CLOB对象 */
        ResultSet rs = stmt.executeQuery("SELECT * FROM TEST_CLOB WHERE ID='111'");
        while (rs.next()) {
          /* 获取CLOB对象 */
          oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
          /* 以字符形式输出 */
          BufferedReader in = new BufferedReader(clob.getCharacterStream());
          BufferedWriter out = new BufferedWriter(new FileWriter(outfile));
          int c;
          while ((c=in.read())!=-1) {
            out.write(c);
          }
          out.close();
          in.close();
        }
      } catch (Exception ex) {
        conn.rollback();
        throw ex;
      }
  
      /* 恢复原提交状态 */
      conn.setAutoCommit(defaultCommit);
    }
  
    /**
    * 向数据库中插入一个新的BLOB对象
    *
    * @param infile - 数据文件
    * @throws java.lang.Exception
    * @roseuid 3EDA04E300F6
    */
    public static void blobInsert(String infile) throws Exception
    {
      /* 设定不自动提交 */
      boolean defaultCommit = conn.getAutoCommit();
      conn.setAutoCommit(fal
相关内容
赞助商链接