Convert between CLOB/BLOB and String.

1. Use the dbms_lob.substr() method to convert the corresponding fields into strings as follows:

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1. select dbms_lob.substr(content) from NEWS    

This method has a disadvantage. When the length of the content field exceeds a certain value, an error will be reported.

2. Get the Clob object, and get the field content by stream processing in Java, there is no length limit in this method

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1. select content from NEWS  

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1. // Convert word CLOB to STRING type   
2.     public String ClobToString(Clob clob) throws SQLException, IOException {   
3.           
4.         String reString = "";   
5.         java.io.Reader  is  =  clob .getCharacterStream();// Get the stream   
6.         BufferedReader br = new BufferedReader(is);   
7.         String s = br.readLine();   
8.         StringBuffer sb = new StringBuffer();   
9.         while (s != null) {// Execute the loop to take out all the strings and pay them to StringBuffer from StringBuffer to STRING   
10.             sb.append(s);   
11.             s = br.readLine();   
12.         }   
13.         reString = sb.toString();   
14.         return reString;   
15.     }   

The next point is to convert the object of the field obtained from the database into a Clob object, as follows:

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1. String content = ClobToString((Clob)obj[1]);  

Among them, my obj is the field array obtained from the database, and obj[1] corresponds to the Clob object

String s1="走上编程不归路……";

         

  Clob c =newSerialClob(s1.toCharArray());//String 转 clob

  Blob b =newSerialBlob(s1.getBytes("GBK"));//String 转 blob

// 也可以这样不传字符集名称，默认使用系统的

//  Blob b = new SerialBlob(s1.getBytes());

  String clobString = c.getSubString(1, (int) c.length());//clob 转 String

  String blobString =newString(b.getBytes(1, (int) b.length()),"GBK");//blob 转 String

//  前面若没传入字符集名称，则这里也不需要传入，以免出错

//  String blobString = new String(b.getBytes(1, (int) b.length()));

  

        System.out.println(clobString);

        System.out.println(blobString);



    // Convert word CLOB to STRING type  

1. String content = ClobToString((Clob)obj[1]); 
   

1.     public String ClobToString(Clob clob) throws SQLException, IOException {   
2.           
3.         String reString = "";   
4.         java.io.Reader is = clob.getCharacterStream();// 得到流   
5.         BufferedReader br = new BufferedReader(is);   
6.         String s = br.readLine();   
7.         StringBuffer sb = new StringBuffer();   
8.         while (s != null) {// 执行循环将字符串全部取出付值给StringBuffer由    StringBuffer转成STRING   
9.             sb.append(s);   
10.             s = br.readLine();   
11.         }   
12.         reString = sb.toString();   
13.         return reString;   
14.     }  
    

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Personal classification:   java basic Oracle