一、设置登录系统的账号密码

        1、在application文件中设置

spring.security.user.name=tom
spring.security.user.password=123

        但是密码明文写在文档中，总归是不好的。

        2、编写类实现接口  

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {

        BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
        //给密码123加密
        String password = passwordEncoder.encode("123");
        auth.inMemoryAuthentication().withUser("tom").password(password).roles("admin");
    }

    @Bean
    PasswordEncoder password() {
        return new BCryptPasswordEncoder();
    }
}

        其实写在代码中也不是很好，一般我们都是从数据库中拿用户名和密码。

二、实现数据库认证完成用户登录

        1、准备sql 

CREATE TABLE users(
 id BIGINT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(20) UNIQUE NOT NULL,
PASSWORD VARCHAR(100)
);
-- 密码 atguigu
INSERT INTO users VALUES(1,'张
san','$2a$10$2R/M6iU3mCZt3ByG7kwYTeeW0w7/UqdeXrb27zkBIizBvAven0/na');
-- 密码 atguigu
INSERT INTO users VALUES(2,'李
si','$2a$10$2R/M6iU3mCZt3ByG7kwYTeeW0w7/UqdeXrb27zkBIizBvAven0/na');
CREATE TABLE role(
id BIGINT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(20)
);
INSERT INTO role VALUES(1,'管理员');
INSERT INTO role VALUES(2,'普通用户');
CREATE TABLE role_user(
uid BIGINT,
rid BIGINT
);
INSERT INTO role_user VALUES(1,1);
INSERT INTO role_user VALUES(2,2);
CREATE TABLE menu(
id BIGINT PRIMARY KEY AUTO_INCREMENT,
NAME VARCHAR(20),
url VARCHAR(100),
parentid BIGINT,
permission VARCHAR(20)
);
INSERT INTO menu VALUES(1,'系统管理','',0,'menu:system');
INSERT INTO menu VALUES(2,'用户管理','',0,'menu:user');
CREATE TABLE role_menu(
MID BIGINT,
rid BIGINT
);
INSERT INTO role_menu VALUES(1,1);

        2、添加依赖

<!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.37</version>
        </dependency>
        <!--lombok 用来简化实体类-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        3、实体类 

@Data
public class Users {
    private Integer id;
    private String username;
    private String password;
}

        4、mapper （使用mabtis-plus）

@Repository
public interface UsersMapper extends BaseMapper<Users> {
}

        5、登录的实现类 

@Service("UserDetailsService")
public class MyUserDetailsService implements UserDetailsService {

    @Autowired
    private UsersMapper usersMapper;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {

        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("username", username);
        Users users = usersMapper.selectOne(queryWrapper);

        if(users == null){
            throw new UsernameNotFoundException("用户名不存在！");
        }

        //数据库搜索获得数据
        List<GrantedAuthority> auths = AuthorityUtils.commaSeparatedStringToAuthorityList("role");
        return new User(users.getUsername(), new BCryptPasswordEncoder().encode(users.getPassword()), auths);
    }
}

        6、配置数据库 

#mysql 数据库连接
spring.datasource.driver-class-name=com.mysql.jdbc.Driver 
spring.datasource.url=jdbc:mysql://localhost:3308/demo?serverTimezone=GMT%2B8 
spring.datasource.username=root 
spring.datasource.password=root