介绍Spring Security框架，以及如何使用它实现应用程序的安全性

<dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-web</artifactId>
    <version>5.0.7.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-config</artifactId>
    <version>5.0.7.RELEASE</version>
</dependency>

import org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer;
public class SecurityInitializer extends AbstractSecurityWebApplicationInitializer {
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
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 SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(Http
Security http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/public/**").permitAll() // 允许所有用户访问公共资源
                .anyRequest().authenticated() // 其他请求需要身份验证
                .and()
            .formLogin() // 启用表单登录
                .loginPage("/login") // 指定自定义登录页面的 URL
                .defaultSuccessURL("/dashboard") // 登录成功后的默认跳转页面
                .permitAll() // 允许所有用户访问登录页面
                .and()
            .logout() // 启用注销功能
                .logoutUrl("/logout") // 指定注销的 URL
                .permitAll(); // 允许所有用户注销
    }
    @Override
    public void configure(WebSecurity web) throws Exception {
        // 配置静态资源不需要身份验证
        web.ignoring().antMatchers("/css/**", "/js/**", "/images/**");
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.crypto.factory.PasswordEncoderFactories;
import org.springframework.security.crypto.password.PasswordEncoder;
@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Bean
    @Override
    public UserDetailsService userDetailsService() {
        PasswordEncoder passwordEncoder = PasswordEncoderFactories.createDelegatingPasswordEncoder();
        UserDetails user = User.builder()
            .username("user")
            .password(passwordEncoder.encode("password"))
            .roles("USER")
            .build();
        UserDetails admin = User.builder()
            .username("admin")
            .password(passwordEncoder.encode("admin"))
            .roles("ADMIN")
            .build();
        return new InMemoryUserDetailsManager(user, admin);
    }
}