小编cha*_*ean的帖子

我正在尝试从我的Java EE程序向需要证书身份验证的主机发送HTTPS请求.我有一个正确的密钥库文件,信任库和导入的CA,两个列表都显示证书在里面.

但是我收到以下错误:

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: KeyUsage does not allow digital signatures
    at ...

...

Caused by: sun.security.validator.ValidatorException: KeyUsage does not allow digital signatures
    at sun.security.validator.EndEntityChecker.checkTLSServer(EndEntityChecker.java:270)
    at sun.security.validator.EndEntityChecker.check(EndEntityChecker.java:141)
    at sun.security.validator.Validator.validate(Validator.java:264)
    at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:326)
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:231)
    at     sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:126)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1319)
... 29 more

在扩展部分中查看证书内容我看到以下内容:

Extensions:

#1: ObjectId: 2.5.29.14 Criticality=false
SubjectKeyIdentifier [
KeyIdentifier [
0000: 33 87 72 1D 09 2F DF FF   1A A7 D1 C0 E1 CF C5 FA  3.r../..........
0010: A4 19 54 2E                                        ..T.
]
]

#2: ObjectId: 2.16.840.1.113730.1.1 Criticality=false …

是否可以根据子类类型动态识别T作为返回类型？我想要以下内容:

public class Parent {
        public <T extends Parent> T foo() {
                return (T)this;
        }
}

public class Child extends Parent {
        public void childMethod() {
                System.out.println("childMethod called");
        }
}

然后致电:

Child child = new Child();
child.foo().childMethod();

没有像这样定义类型:

Child child = new Child();
child.foo().<Child>childMethod(); // compiles fine

提前致谢!