Question

我制作了将给定值（来自数组指针）拆分为字节的函数。为简单起见，我使用一个字节值。为什么在打印值时会出现奇怪的数字？

public class CustomIdTokenConverter extends DefaultUserAuthenticationConverter {

    private final JwkTokenStore jwkTokenStore;

    public CustomIdTokenConverter(String keySetUri) {
        this.jwkTokenStore = new JwkTokenStore(keySetUri);
    }

    @Override
    public Authentication extractAuthentication(Map<String, ?> map) {

        String idToken = (String) map.get("id_token");

        OAuth2AccessToken token = jwkTokenStore.readAccessToken(idToken);

        Map<String, Object> claims = token.getAdditionalInformation();
        OAuth2RefreshToken refreshToken = token.getRefreshToken();

        String principal = (String) claims.get("sub");

        List<GrantedAuthority> authorities = AuthorityUtils.createAuthorityList("ROLE_USER");

        return new CustomAuthenticationData(principal, claims, authorities);
    }
}

输出

2552030

0

119944479905023

255

1

70453687222272

0 2

0

0

Answer 1

如果您的目标是采用任何类型并破坏字节，那么几乎总是这样做的方法是将指向该类型的指针转换为char *并使用char * 。

这是一个使用精简代码的示例。

#include <iostream>

struct foo
{
    int x;
    double y;
    char z;
};

void writePage(uint16_t address, char *data, uint8_t const len)
{
    for (uint8_t dataIndex = 0; dataIndex < len; dataIndex++)
    {
        std::cout << (int)data[dataIndex] << std::endl;
    }
}

int main()
{
    uint8_t array[3] = { 255, 20, 30 };
    std::cout << int(array[0]) << " " << int(array[1]) << " " << int(array[2]) << std::endl;
    writePage(0, reinterpret_cast<char *>(&array[0]), sizeof(array));
    foo f;
    f.x = 10;
    f.y = 20;
    f.z = 'g';
    std::cout << "Here are the bytes of foo, which has a sizeof(foo) as " << sizeof(foo) << "\n" ;
    writePage(0, reinterpret_cast<char *>(&f), sizeof(f));
    return 0;
}

输出：

255 20 30
-1
20
30
Here are the bytes of foo, which has a sizeof(foo) as 24
10
0
0
0
0
0
0
0
0
0
0
0
0
0
52
64
103
-54
-117
-54
-2
127
0
0

从数组指针获取奇怪的数字

1 个答案: