在oracle数据库中如何插入CLOB值

﹏ヽ暗。殇╰゛Y 2021-12-16 12:35 513阅读 0赞

轉貼:http://blog.csdn.net/cmtobby/

[oracle][]中最常用的varcher2类型最多只能存储4000个字节的内容，一般情况下是能够满足用户的需求的。但是在一些特殊情况下（如要存储图片或者要存储的内容超过了4000个字节），varcher2就满足不了这个需求了。这个时候我们可以借助于oracle里面的大字段CLOB后者BLOB。举例如下：

首先，在数据库[中建][Link 1]一张表news，为了简单起见，只有一个字段content（CLOB）。做好准备工作后就可以开始我们的CLOB之旅了。

以下是插入CLOB的代码：

import java.sql.\*;  
         import java.io.\*;

public class TestClob\{  
               public void TestClob()\{\}  
                      public static void main(String args\[\])\{  
                              try\{  
                                   Class.forName("oracle.jdbc.driver.OracleDriver");  
                                  Connectionconn=DriverManager.getConnection ("jdbc:oracle:thin:@localhost:1521:ora32","tjpt","tjpt");  
   
                                 conn.setAutoCommit(false);  
                                //第一步：插入一个空的CLOB  
                                String sql1="insert into news(content,id) values (EMPTY\_CLOB(),'1')";  
                                PreparedStatement ps1=conn.prepareStatement(sql1);  
                                ps1.executeUpdate();  
                                ps1.close();  
   
                                //第二步：取出该CLOB  
                                String sql2="select content from news for update";  
                                PreparedStatement ps2=conn.prepareStatement(sql2);  
                                ResultSet rs2=ps2.executeQuery();  
                                while (rs2.next())\{  
                                        oracle.sql.CLOB clob=(oracle.sql.CLOB)rs2.getClob(1);  
                                        BufferedWriter out=new BufferedWriter(clob.getCharacterOutputStream());  
                                        String content="1234";//假定这是新闻的内容，当然可以也可以是其他的内容  
                                        out.write(content,0,content.length());  
                                        out.close();  
                                                               \}  
                               conn.commit();  
                             \}  
         catch(Exception e)\{e.printStackTrace();\}  
  \}

既然插入进去了，那我们还得要检验一下：插进去的是不是你想插进去的内容？以下就是读取CLOB的代码：

import java.sql.\*;  
import java.io.\*;  
public class ReadClob\{  
 public void ReadClob()\{\}  
 public static void main(String args\[\])\{  
 try\{  
  Class.forName("oracle.jdbc.driver.OracleDriver");  
  Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ora32","tjpt","tjpt");                                                          String sql1="select content from news";  
  PreparedStatement ps1=conn.prepareStatement(sql1);  
  ResultSet rs1=ps1.executeQuery();  
  while (rs1.next())\{  
   oracle.sql.CLOB clob=(oracle.sql.CLOB)rs1.getClob(1);  
   BufferedReader in=new BufferedReader(clob.getCharacterStream());  
   StringWriter out=new StringWriter();  
   int c;  
   while((c=in.read())!=-1)\{  
    out.write(c);  
   \}  
   String content=out.toString();  
   System.out.println (content);//输出CLOB内容  
  \}  
 \}  
 catch(Exception e)\{e.printStackTrace();\}  
 \}  
\}

再分享一下我老师大神的人工智能教程吧。零基础！通俗易懂！风趣幽默！还带黄段子！希望你也加入到我们人工智能的队伍中来！[https://blog.csdn.net/jiangjunshow][https_blog.csdn.net_jiangjunshow]

转载于:https://www.cnblogs.com/skiwdhwhssh/p/10340805.html

[oracle]: https://www.baidu.com/s?wd=oracle&tn=24004469_oem_dg&rsv_dl=gh_pl_sl_csd
[Link 1]: https://www.baidu.com/s?wd=%E4%B8%AD%E5%BB%BA&tn=24004469_oem_dg&rsv_dl=gh_pl_sl_csd
[https_blog.csdn.net_jiangjunshow]: https://blog.csdn.net/jiangjunshow/article/details/77338485