01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
package horstmann.ch07_reflect2;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Random;
/**
This program shows how to use reflection to print
the names and values of all nonstatic fields of an object.
*/
public class FieldTester
{
public static void main(String[] args)
throws IllegalAccessException
{
Random r = new Random();
System.out.print(spyFields(r));
r.nextInt();
System.out.println("\nAfter calling nextInt:\n");
System.out.print(spyFields(r));
}
/**
Spies on the field names and values of an object.
@param obj the object whose fields to format
@return a string containing the names and values of
all fields of obj
*/
public static String spyFields(Object obj)
throws IllegalAccessException
{
StringBuilder buffer = new StringBuilder();
Field[] fields = obj.getClass().getDeclaredFields();
for (Field f : fields)
{
if (!Modifier.isStatic(f.getModifiers()))
{
f.setAccessible(true);
Object value = f.get(obj);
buffer.append(f.getType().getName());
buffer.append(" ");
buffer.append(f.getName());
buffer.append("=");
buffer.append("" + value);
buffer.append("\n");
}
}
return buffer.toString();
}
}
|
