String(bytes [] Charset)在Java7和java 8中以不同的方式返回结果

2024年1月25日 240次阅读 
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;

public class Java87String {

public static void main(String[] args) throws UnsupportedEncodingException {
        // TODO Auto-generated method stub

        //byte[] b = {-101, 53, -51, -26, 24, 60, 20, -31, -6, 45, 50, 103, -66, 28, 114, -39, 92, 23, -47, 32, -5, -122, -28, 79, 22, -76, 116, -122, -54, -122};
        //byte[] b = {-76, -55, 85, -50, 80, -23, 27, 62, -94, -74, 47, -123, -119, 94, 90, 61, -63, 73, 56, -48, -54, -4, 11, 79};

        byte[] b = { -5, -122, -28};

        System.out.println("Input Array :" + Arrays.toString(b));
        System.out.println("Array Length : " + b.length);                       
        String target = new String(b,StandardCharsets.UTF_8);
        System.out.println(Arrays.toString(target.getBytes("UTF-8")));
        System.out.println("Final Key :" + target);

}
}

上面的代码在Java 7中返回以下输出

Input Array :[-5, -122, -28]
Array Length : 3
[-17, -65, -67]
Final Key :�

相同的代码在Java 8中返回以下输出

Input Array :[-5, -122, -28]
Array Length : 3
[-17, -65, -67, -17, -65, -67, -17, -65, -67]
Final Key :���

听起来像Java8正在用[-17,-65,-67]的默认序列替换正确的东西.

为什么JDK 1.7中的输出和任何已知错误都存在差异而修复了这个问题？

最佳答案 按
String JavaDoc：

The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.

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