java读取显示/写入oracle long类型

最新推荐文章于 2024-08-29 03:46:31 发布

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最新推荐文章于 2024-08-29 03:46:31 发布

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分类专栏： Oracle 文章标签： oracle java string file query stream

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本文探讨了使用JSP和Oracle进行数据交互时遇到的问题，包括如何正确处理Oracle中的long类型数据，在Java中读取及在JSP中写入的方法，并提供了一段示例代码。

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使用jsp和oracle过程中遇到如下的问题
（1）在oracle中写存储过程并且在java中读取发现没法用getString获取long类型.而一起取出的其他varchar2都能作为String值取出
String content=rs.getString("content"); //取不到值显示null

问下如何做才能将long类型值取出并且在一个textarea中显示？
（2）在jsp中我用String类型来获取textarea的值并且将其写入long字段。这样是可行的
cstmt.setString(9,content); //输入第九为long类型字段，content为字符串。
但是不知道这样输入会不会对输入的数据造成什么破坏。
是不是有更好的方法来将textarea的数据输入oracle的long字段。

Code for inserting Long Data

public void insertData(String code, String name, String partner, 
                       String textfile) throws Exception {
    
  // Create a File to read data from the specified text file (textfile)
  File file = 
    new File(getClass().getClassLoader().getResource(textfile).getFile());
    
  // Prepare the statement for inserting a row into the OTN_AIRLINES_LONG
  PreparedStatement pstmt = connection.prepareStatement(" INSERT INTO "+
                          "otn_airlines_long( code, name, partner,"+
                          "airline_insurance_data) VALUES(?, ?, ?, ?)");
    
    // Bind the parameter values for the above statement
    pstmt.setString(1, code); 
    pstmt.setString(2, name); 
    pstmt.setString(3, partner);
    
    // Bind the AIRLINE_INSURANCE_DATA column to an input Ascii stream that
    // returns the Ascii data to be inserted into the LONGRAW column
    pstmt.setCharacterStream(4, new FileReader(file), (int)file.length());
    
    // Execute the statement
    pstmt.execute();
  }
}
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Code for retrieving Long Data

public void displayLongData(String code) {
........
........
  // Create a PreparedStatement object to execute the QUERY
  PreparedStatement pst = 
    connection.prepareStatement("SELECT airline_insurance_data"+
                        " FROM otn_airlines_long WHERE code = ?");
      
  // Bind the airline code to the query
  pst.setString(1, code);
    gui.putStatus("Reading Long Column from the DB, Please wait...");
      
  // Excute the Query
  ResultSet resultSet = pst.executeQuery();
      
  // Populate the ResultSet
  while(resultSet.next()) {
    InputStream insurancedata; // Holds the LONG data
    StringBuffer dataBuffer = new StringBuffer();
        
    /* Obtain the LONG data into a byte array. LONG data can be accessed in 
    two ways: 1) By retrieving all the data in one shot (getBytes method)
    2) By using streams. The LONG data is made available to the program
    as an Ascii or Unicode stream, and the data can be retrieved chunk by
    chunk, which is more eficient in terms of memory usage        
    In this sample we illustrate retrieval using streams */
    insurancedata = resultSet.getAsciiStream(1);
    while((chunk = insurancedata.read()) != -1) {
      dataBuffer.append((char)chunk);
    }
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