java 读取Oracle的clob，blob转换为字符串

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java 读取clob，blob转换为字符串

/***
* 读取oracleCLOB字段内容
* @param conn
* @return
*/
public static String readCLOB(Connection conn) {
  String sql = "select 大字段1,大字段2 from 印章基本信息_char_ccbb where yzbm='2'";
  String content = "";
  try {
   conn.setAutoCommit(false);
   PreparedStatement ps1 = conn.prepareStatement(sql);
   ResultSet rs1 = ps1.executeQuery();
   while (rs1.next()) {
    oracle.sql.CLOB clob = (oracle.sql.CLOB) rs1.getClob("大字段1");

    BufferedReader in = new BufferedReader(clob
      .getCharacterStream());
    StringWriter out = new StringWriter();
    int c;
    while ((c = in.read()) != -1) {
     out.write(c);
    }
    content = out.toString();
    System.out.println(content);// 输出CLOB内容
   }
  } catch (Exception e) {
   e.printStackTrace();
  }

return content;
}

/***
* 读取oracle的blob转换为字符串
* @param conn
* @return
*/

public static String ConvertBLOBtoString(Connection conn){
  String newStr = ""; // 返回字符串
  long BlobLength; // BLOB字段长度
  byte[] bytes; // BLOB临时存储字节数组
  int i = 1; // 循环变量
  Statement st =null;
  try {
   st = conn.createStatement();
   ResultSet rs = st
     .executeQuery("select 大字段2 from 印章基本信息_char_ccbb where yzbm='2'");
   while (rs.next()) {
    BLOB blob = (BLOB) rs.getBlob("大字段2");
    byte[] msgContent = blob.getBytes(); // BLOB转换为字节数组
    BlobLength=blob.length(); //获取BLOB长度
    if (msgContent == null || BlobLength==0) //如果为空，返回空值
        {
          return "";
        }else{
     while(i<BlobLength)             //循环处理字符串转换，每次1024；Oracle字符串限制最大4k
           {
             bytes= blob.getBytes(i,1024) ;
             i=i+1024;
             newStr = newStr+new String(bytes,"gb2312") ;
           }
        }
   }
   System.out.println(newStr);
   System.out.println(newStr.length());

  } catch (UnsupportedEncodingException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } finally{
   if(st!=null){
    try {
     st.close();
    } catch (SQLException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
   try {
    conn.close();
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  return newStr;
}

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