There is no PasswordEncoder mapped for the id "null"

在spring-security登陆时报错：There is no PasswordEncoder mapped for the id “null”

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版本问题

用spring-security5.0以上报错

使用内存获取认证信息

 auth
                .inMemoryAuthentication()
                .withUser("user").password("password").roles("USER");

出现报错

java.lang.IllegalArgumentException: There is no PasswordEncoder mapped for the id "null"
	at org.springframework.security.crypto.password.DelegatingPasswordEncoder$UnmappedIdPasswordEncoder.matches(DelegatingPasswordEncoder.java:244) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.crypto.password.DelegatingPasswordEncoder.matches(DelegatingPasswordEncoder.java:198) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration$LazyPasswordEncoder.matches(AuthenticationConfiguration.java:289) ~[spring-security-config-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.authentication.dao.DaoAuthenticationProvider.additionalAuthenticationChecks(DaoAuthenticationProvider.java:90) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider.authenticate(AbstractUserDetailsAuthenticationProvider.java:166) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:175) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:200) ~[spring-security-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]

原因

Spring security 5.0中新增了多种加密方式，也改变了密码的格式。

解决方法

auth.inMemoryAuthentication().passwordEncoder(new BCryptPasswordEncoder()).withUser("user").password(new BCryptPasswordEncoder().encode("password")).roles("USER");

另外

是从数据库中获取认证信息的话，这样写

auth.userDetailsService(userService).passwordEncoder(new BCryptPasswordEncoder());