逻辑删除（假删除）

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已于 2024-07-25 19:01:48 修改

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文章标签：笔记

于 2024-07-15 20:50:02 首次发布

原文链接：https://www.bilibili.com/video/BV16w4m1e7QX/?spm_id_from=333.999.0.0&vd_source=367f708f2306ab313c8cc0f6b3de3fae

版权

创建一个拦截器LogicDeleteInterceptor

@Intercepts(
        @Signature(type= StatementHandler.class,method = "prepare",args = {Connection.class,Integer.class})
)
@Component
public class LogicDeleteInterceptor implements Interceptor, HandlerInterceptor {
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        //invocation获取原始对象
        StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
        //获取旧有得sql语句
        BoundSql boundSql = statementHandler.getBoundSql();
        String oldSQL = boundSql.getSql();
        String newSQL = oldSQL.replace("where 1=1","where 1=1 and is_deleted=0");
        //用newSQL替换oldSQL
        Field sql = boundSql.getClass().getDeclaredField("sql");
        sql.setAccessible(true);
        sql.set(boundSql,newSQL);
        //调用原始对象执行原始方法且返回
        return invocation.proceed();


    }
}

在WebConfig中注册拦截器

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private LoginInterceptor loginInterceptor;

    @Autowired
    private LogicDeleteInterceptor logicDeleteInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logicDeleteInterceptor);
        //登录接口和注册接口不拦截
        registry
                .addInterceptor(loginInterceptor)
                .excludePathPatterns("/user/login","/user/register");

    }

}

sql语句写法

逻辑删除时，controller使用@DeleteMapping，在mapper层使用<update>标签

检查用户名是否被暂用

public boolean isUsernameAvailable(String username) {
    // 检查数据库中是否存在该用户名，包括逻辑删除的用户
    User user = userRepository.findByUsername(username);
    if (user == null || user.isDeleted()) {
        // 用户不存在或已被逻辑删除，用户名可用
        return true;
    } else {
        // 用户存在且未被删除，用户名不可用
        return false;
    }
}

public User saveUser(User user) {
    if (isUsernameAvailable(user.getUsername())) {
        // 用户名可用，保存新用户
        return userRepository.save(user);
    } else {
        // 用户名不可用，抛出异常或返回错误信息
        throw new UsernameNotAvailableException("用户名已被占用");
    }
}