And another thing I don't understand, if I compare a string with a clob (identical values), the code that compares the clob is used, whereas instanceof is not supposed to be identical...! Here
What I expect is my code: when I compare 2 differents clobs, comparison as objects is false, as string (simplified for exampletoString output): is false, it detects that objects are instanceof clobs, so convert them as string, and then compare string values.
Here is my code (simplified for example):
import java.io.*;
import java.sql.*;
import javax.sql.rowset.serial.*;
public class TestClob {
public static void main(String[] args) throws SerialException, SQLException {
boolean result;
Object text1="abcdef", text2="abcdef";
Clob clob1 = new SerialClob(((String) text1).toCharArray());
Clob clob2 = new SerialClob(((String) text2).toCharArray());
Clob clob3 = new SerialClob("abcdefg".toCharArray());
System.out.println("TEST 1, basic string comparison");
System.out.println("-------------------------------");
result = haveSameValue(text1, text2);
System.out.println("result: "+result);
System.out.println("\nTEST 2, clob vs string");
System.out.println("----------------------");
result = haveSameValue(clob1, text1);
System.out.println("result: "+result);
System.out.println("\nTEST 3, different clobs objects but same value");
System.out.println("----------------------------------------------");
result = haveSameValue(clob1, clob2);
System.out.println("result: "+result);
System.out.println("\nTEST 4, different clobs");
System.out.println("-----------------------");
result = haveSameValue(clob1, clob3);
System.out.println("result: "+result);
}
public static boolean haveSameValue(Object obj1, Object obj2) {
String sObj1, sObj2, sObj1Class, sObj2Class;
boolean result = true;false;
if (obj1!=null && obj2!=null) {
sObj1Class = obj1.getClass().toString().toLowerCase();
sObj2Class = obj2.getClass().toString().toLowerCase();
System.out.println(" Objects class : sObj1Class="+sObj1Class+", sObj2Class="+sObj2Class);
System.out.println(" OBJECT : obj1="+obj1+", obj2="+obj2+", => equal as object? "+obj1.equals(obj2));
if (!obj1.equals(obj2)) {
sObj1=obj1.toString();
sObj2=obj2.toString();
System.out.println(" STRING : sObj1="+sObj1+", sObj2="+sObj2+", => equal as string? "+sObj1.equals(sObj2));
if (!sObj1.equals(sObj2)) {
if (obj1 instanceof java.sql.Clob || obj2 instanceof java.sql.Clob) {
sObj1 = ClobToString(obj1);
sObj2 = ClobToString(obj2);
System.out.println(" CLOB : sObj1="+sObj1+", sObj2="+sObj2+" => equal as clob? "+sObj1.equals(sObj2));
result = sObj1.equals(sObj2);
}
// other comparisons (as a date, timestamp, number...)
}
}
}
return result;
}
public static String ClobToString(Object object) {
if (object==null) {
return null;
}
else if (object instanceof java.sql.Clob) {
StringBuilder sb = new StringBuilder();
try {
Reader reader = ((java.sql.Clob) object).getCharacterStream();
BufferedReader br = new BufferedReader(reader);
String line;
while(null != (line = br.readLine())) {
sb.append(line);
}
br.close();
return sb.toString();
}
catch (Exception e) {
System.out.println("error : "+e.getMessage());
return object.toString();
}
}
else {
return object.toString();
}
}
}