4回答

• 

  慕斯0471166

  2016-05-01 01:55:01

  已采纳

  public class Ckb_test {  
    
      public static void main(String[] args) throws SQLException, IOException {  
          // TODO Auto-generated method stub  
          read();  
      }  
      static void create() throws SQLException, IOException  
      {  
          Connection conn=null;  
          PreparedStatement prest=null;  
          ResultSet resultset=null;  
            
          try {  
              //2.建立连接  
              conn=JdbcUtils.getConnection();  
              //单例设计模式  
              conn=JdbcUtilsSingle.getInstance().getConnection();  
              //3.创建语句  
              String sql="insert into ckb_test(text) values(?)";  
              prest=conn.prepareStatement(sql);  
              File file=new File("src/cn/com/JDBC/JdbcUtils.java");  
              Reader reader=new BufferedReader(new FileReader(file));  
              prest.setCharacterStream(1, reader, (int)file.length());  
              //4.执行语句  
                
              int i=prest.executeUpdate();  
              reader.close();  
              System.out.println("i="+i);  
          } finally  
          {  
              JdbcUtils.free(resultset, prest, conn);  
          }  
      }  
      static void read() throws SQLException, IOException  
      {  
          Connection conn=null;  
          Statement st=null;  
          ResultSet resultset=null;  
            
          try {  
              //2.建立连接  
              conn=JdbcUtils.getConnection();  
              //单例设计模式  
              conn=JdbcUtilsSingle.getInstance().getConnection();  
              //3.创建语句  
              st=conn.createStatement();  
              //4.执行语句  
              resultset=st.executeQuery("select text from ckb_test");  
              //5.处理结果  
              while(resultset.next())  
              {  
                  Clob clob=resultset.getClob(1);  
                  Reader reader=clob.getCharacterStream();  
                  //reader=resultset.getCharacterStream(1);  
                  File file=new File("JdbcUtils.java");  
                  Writer writer=new BufferedWriter(new FileWriter(file));  
                  char[] buff=new char[1024];  
                  for(int i=0;(i=reader.read(buff))>0;)  
                  {  
                      writer.write(buff,0,i);  
                  }  
                  writer.close();  
                  reader.close();  
              }  
                
          } finally  
          {  
              JdbcUtils.free(resultset, st, conn);  
          }  
      }  
    
  }  
    
  ----------------------------------------------------------------------------------------------------------  
  
  public class PictureBlob {  
    
      public static void main(String[] args) throws SQLException, IOException {  
          read();  
      }  
      static void create() throws SQLException, IOException  
      {  
          Connection conn=null;  
          PreparedStatement prest=null;  
          ResultSet resultset=null;  
            
          try {  
              //2.建立连接  
              conn=JdbcUtils.getConnection();  
              //单例设计模式  
              conn=JdbcUtilsSingle.getInstance().getConnection();  
              //3.创建语句  
              String sql="insert into blob_test(big_bit) values(?)";  
              prest=conn.prepareStatement(sql);  
              File file=new File("C:\\Documents and Settings\\Administrator\\My Documents\\My Pictures\\cxg.jpg");  
              InputStream in=new BufferedInputStream(new FileInputStream(file));  
              prest.setBinaryStream(1, in, (int)file.length());  
              //4.执行语句  
                
              int i=prest.executeUpdate();  
              in.close();  
              System.out.println("i="+i);  
          } finally  
          {  
              JdbcUtils.free(resultset, prest, conn);  
          }  
            
      }  
        
      static void read() throws SQLException, IOException  
      {  
          Connection conn=null;  
          Statement st=null;  
          ResultSet resultset=null;  
            
          try {  
              //2.建立连接  
              conn=JdbcUtils.getConnection();  
              //单例设计模式  
              conn=JdbcUtilsSingle.getInstance().getConnection();  
              //3.创建语句  
              st=conn.createStatement();  
              //4.执行语句  
              resultset=st.executeQuery("select big_bit from blob_test");  
              //5.处理结果  
              while(resultset.next())  
              {  
                  Blob blob=resultset.getBlob(1);  
                  InputStream in=blob.getBinaryStream();  
                  //reader=resultset.getCharacterStream(1);  
                  File file=new File("1.jpeg");  
                  OutputStream out=new BufferedOutputStream(new FileOutputStream(file));  
                  byte[] buff=new byte[1024];  
                  for(int i=0;(i=in.read(buff))>0;)  
                  {  
                      out.write(buff,0,i);  
                  }  
                  out.close();  
                  in.close();  
              }  
                
          } finally  
          {  
              JdbcUtils.free(resultset, st, conn);  
          }  
      }  
  }

  
  

  2 1

  Helios...

  我之前写了代码发现上传之后下载下来文件就损坏了。。能帮忙看看吗？

  2016-05-01 10:19:05

  共 2 条回复 >

• 

  Helios_

  2016-05-01 10:19:46

  public void upload(String userid, InputStream is) throws SQLException{

  Connection conn=Init.getConnection();

  String sql="" +

  " insert file(userid,file) " +

  " values(?,?) " ;

  PreparedStatement ptmt=conn.prepareStatement(sql);

  ptmt.setString(1, userid);

  ptmt.setBinaryStream(2, is);

  ptmt.execute();

  }

  public InputStream download(String userid) throws SQLException{

  Connection conn=Init.getConnection();

  String sql="" +

  " select * from file " +

  " where userid like ? ";

  PreparedStatement ptmt=conn.prepareStatement(sql);

  ptmt.setString(1, "%"+userid+"%");

  ResultSet rs=ptmt.executeQuery();

  rs.next();

  return rs.getBinaryStream("file");

  }

  
  

  0 0
• 

  慕斯0471166

  2016-05-01 01:46:45

  首先，文件是可以保存到数据库中的，但是不建议这么做（Why请百度）。实际的做法是把文件的路径保存到数据库中，然后读取文件的话先是从数据库中读到路径，再根据路径得到文件，希望能帮到

  0 1
• 

  灿烂满天星

  2016-04-26 23:19:21

  可以自己在数据库中建一个文件夹，然后将图片资源上传到该文件夹中

  0 0