解决java.lang.IllegalArgumentException: There is no PasswordEncoder mapped for the id

使用springboot，权限管理使用spring security，使用内存用户验证，但无响应报错：

java.lang.IllegalArgumentException: There is no PasswordEncoder mapped for the id "null"

解决方法：

这是因为Spring boot 2.0.3引用的security 依赖是 spring security 5.X版本，此版本需要提供一个PasswordEncorder的实例，否则后台汇报错误：

java.lang.IllegalArgumentException: There is no PasswordEncoder mapped for the id "null"

并且页面毫无响应。

因此，需要创建PasswordEncorder的实现类。

MyPasswordEncoder.class:

import org.springframework.security.crypto.password.PasswordEncoder;


public class MyPasswordEncoder implements PasswordEncoder {
    @Override
    public String encode(CharSequence charSequence) {
        return charSequence.toString();
    }

    @Override
    public boolean matches(CharSequence charSequence, String s) {
        return s.equals(charSequence.toString());
    }
}

​ 然后在内存用户中添加：

import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.builders.WebSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

@Configuration
@EnableWebSecurity
public class SpringSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        //可以设置内存指定的登录的账号密码,指定角色
        //不加.passwordEncoder(new MyPasswordEncoder())
        //就不是以明文的方式进行匹配，会报错
        auth.inMemoryAuthentication().withUser("admin").password("123456").roles("ADMIN");
        //.passwordEncoder(new MyPasswordEncoder())。
        //这样，页面提交时候，密码以明文的方式进行匹配。
        auth.inMemoryAuthentication().passwordEncoder(new MyPasswordEncoder()).withUser("cxh").password("cxh").roles("ADMIN");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
       //设置登录,注销，表单登录不用拦截，其他请求要拦截
        http.authorizeRequests().antMatchers("/").permitAll()
                .anyRequest().authenticated()
                .and()
                .logout().permitAll()
                .and()
                .formLogin();
        //关闭默认的csrf认证
        http.csrf().disable();

    }

    @Override
    public void configure(WebSecurity web) throws Exception {
        //设置静态资源不要拦截
        web.ignoring().antMatchers("/js/**","/cs/**","/images/**");
    }
}

最后运行：输入账号cxh密码：cxh,验证成功才显示信息：，如果输入admin/123456就会报错，重新跳回到登录页面，因为admin的用户我没用 new MyPasswordEncorder进行明文匹配