Find all triplets $ (x,y,z) $ of positive integers such that
\[ x^y + y^x = z^y \]\[ x^y + 2012 = y^{z+1} \]
To find all triplets \((x, y, z)\) of positive integers such that
\[ x^y + y^x = z^y \]
\[ x^y + 2012 = y^{z+1} \]

we will analyze the problem by considering different cases for \(x\) and \(y\).

1. **Case 1: \(x\) is even**

   - Let \(x = 2k\) for some integer \(k\).
   - Consider \(y \ge 3\):
     - The left-hand side (LHS) of the first equation \(x^y + y^x\) modulo 8 is \(4\) (since \(x^y\) is a multiple of \(4\) and \(y^x\) is odd).
     - Therefore, \(z^y \equiv 4 \pmod{8}\), which implies \(z\) must be even.
     - However, if \(z+1 \le 2\), then \(z = 1\), which contradicts the first equation since \(x^y + y^x \neq 1\).
     - Thus, \(y \le 2\).

   - Now, consider \(y = 2\):
     - The first equation becomes \(x^2 + 2^x = z^2\).
     - The second equation becomes \(x^2 + 2012 = 2^{z+1}\).

     Let's solve these equations:
     - From the second equation, \(2^{z+1} = x^2 + 2012\).
     - Taking the logarithm base 2, we get \(z+1 = \log_2(x^2 + 2012)\).
     - Therefore, \(z = \log_2(x^2 + 2012) - 1\).

     - Substitute \(z\) into the first equation:
       \[ x^2 + 2^x = (\log_2(x^2 + 2012) - 1)^2 \]

     - Check for possible values of \(x\):
       - For \(x = 6\):
         - \(6^2 + 2^6 = 36 + 64 = 100\)
         - \(z = \log_2(6^2 + 2012) - 1 = \log_2(36 + 2012) - 1 = \log_2(2048) - 1 = 11 - 1 = 10\)
         - Thus, \(z = 10\).

       - Verify the second equation:
         - \(6^2 + 2012 = 36 + 2012 = 2048\)
         - \(2^{10+1} = 2^{11} = 2048\)

       - Therefore, \((x, y, z) = (6, 2, 10)\) is a solution.

2. **Case 2: \(x\) is odd**

   - Let \(x = 2k+1\) for some integer \(k\).
   - Since \(x\) is odd, \(y\) must also be odd for \(z\) to be even (as \(z^y\) must be a multiple of 4).
   - Since \(y > 1\), \(z^y\) is a multiple of 4, implying \(x + y\) is a multiple of 4.

   - Consider the second equation modulo 4:
     - \(x^y + 2012 \equiv y^{z+1} \pmod{4}\)
     - Since \(x\) and \(y\) are odd, \(x^y \equiv 1 \pmod{4}\) and \(y^{z+1} \equiv 1 \pmod{4}\).
     - Therefore, \(1 + 2012 \equiv 1 \pmod{4}\), which is a contradiction since \(2012 \equiv 0 \pmod{4}\).

   - Hence, no solutions exist for \(x\) and \(y\) both being odd.

Conclusion:
The only solution is \((x, y, z) = (6, 2, 10)\).

The final answer is \( \boxed{ (6, 2, 10) } \).