@Test
public void test1() throws Exception {
String s = "ttttttt";
Unsafe u = getUnsafeInstance ();
Field valueInString = String.class.getDeclaredField ( "value" );
long offset = u.objectFieldOffset ( valueInString );
long base = u.arrayBaseOffset ( char[].class );
long scale = u.arrayIndexScale ( char[].class );
char[] values = (char[]) u.getObject ( s, offset );
u.putChar ( values, base + scale, ‘c‘ );
s = "ttttttt";
String s1= "ttttttt";
System.out.println ( "s:" + s );
System.out.println ( "s1:" + s1 );
}
public static Unsafe getUnsafeInstance() throws Exception {
Field unsafeStaticField =
Unsafe.class.getDeclaredField ( "theUnsafe" );
unsafeStaticField.setAccessible ( true );
return (Unsafe) unsafeStaticField.get ( Unsafe.class );
}
@Test public void test2() throws Exception { String s = "eeee"; Field valueInString = String.class.getDeclaredField ( "value" ); valueInString.setAccessible ( true ); char[] chars ={‘a‘,‘c‘,‘c‘}; valueInString.set ( s, chars); System.out.println (s); String s1 = "eeee"; System.out.println (s1); }
原文：https://www.cnblogs.com/JohnBoy/p/10342149.html