Lazy loading only queries when accessing associations can easily lead to N 1 problems, which is suitable for scenarios where the associated data is not determined whether it is needed; 2. Emergency loading uses with() to load associated data in advance to avoid N 1 queries, which is suitable for batch processing scenarios; 3. Emergency loading should be used to optimize performance, and N 1 problems can be detected through tools such as LaravelDebugbar, and the $with attribute of the model is carefully used to avoid unnecessary performance overhead.

Laravel supports the use of native SQL queries, but parameter binding should be preferred to ensure safety; 1. Use DB::select() to execute SELECT queries with parameter binding to prevent SQL injection; 2. Use DB::update() to perform UPDATE operations and return the number of rows affected; 3. Use DB::insert() to insert data; 4. Use DB::delete() to delete data; 5. Use DB::statement() to execute SQL statements without result sets such as CREATE, ALTER, etc.; 6. It is recommended to use whereRaw, selectRaw and other methods in QueryBuilder to combine native expressions to improve security

JWT is an open standard for safe transmission of information. In Java, authentication and authorization can be achieved through the JJWT library. 1. Add JJWT API, Impl and Jackson dependencies; 2. Create JwtUtil tool class to generate, parse and verify tokens; 3. Write JwtFilter intercepts requests and verify BearerTokens in Authorization header; 4. Register Filter in SpringBoot to protect the specified path; 5. Provide a login interface to return JWT after verifying the user; 6. The protected interface obtains user identity and roles through parsing the token for access control, and ultimately realizes a stateless and extensible security mechanism, suitable for distributed systems.

Go generics are supported since 1.18 and are used to write generic code for type-safe. 1. The generic function PrintSlice[Tany](s[]T) can print slices of any type, such as []int or []string. 2. Through type constraint Number limits T to numeric types such as int and float, Sum[TNumber](slice[]T)T safe summation is realized. 3. The generic structure typeBox[Tany]struct{ValueT} can encapsulate any type value and be used with the NewBox[Tany](vT)*Box[T] constructor. 4. Add Set(vT) and Get()T methods to Box[T] without

json.loads() is used to parse JSON strings into Python data structures. 1. The input must be a string wrapped in double quotes and the boolean value is true/false; 2. Supports automatic conversion of null→None, object→dict, array→list, etc.; 3. It is often used to process JSON strings returned by API. For example, response_string can be directly accessed after parsing by json.loads(). When using it, you must ensure that the JSON format is correct, otherwise an exception will be thrown.

Use regular expression capture group in Notepad to effectively reorganize text. First, you need to open the replacement dialog box (Ctrl H), select "Search Mode" as "regular expression", 1. Use () to define the capture group, such as (\w ) to capture words; 2. Use \1 and \2 to reference the corresponding group in the replacement box; 3. Example: Exchange the name "JohnDoe" as "Doe, John", find (\w )\s (\w ), replace it with \2,\1; 4. Date format conversion 2023-12-25 to 25/12/2023, find (\d{4})-(\d{2})-(\d{2}), replace it with \3/\2/\1; 5. Log reordering can extract time, level, ID and other information

Advanced Java interview questions mainly examine the understanding of JVM internal mechanisms, concurrent programming, performance tuning, design patterns and system architecture. 1. The Java memory model (JMM) defines the visibility, atomicity and order of memory operations between threads. The volatile keyword and happens-before rules ensure correct synchronization to avoid the problem of update invisibility caused by CPU cache. G1GC is suitable for large heaps and predictable pause scenarios. Areas with a lot of garbage are preferred through area recycling. ZGC uses shading pointers and loading barriers to achieve submillisecond-level pauses, and the pause time is independent of the heap size, which is suitable for low-latency systems. 2. Use ConcurrentHashMap to design thread-safe LRU cache

Python's ternary operator is used to concisely implement if-else judgment, and its syntax is "value_if_trueif conditionelsevalue_if_false"; 1. It can be used for simple assignment, such as returning the corresponding string based on positive and negative values; 2. It can avoid division errors, such as determining that the denominator is non-zero and then division; 3. It can select content according to conditions in string format; 4. It can assign labels to different elements in list derivation formula; it should be noted that this operator is only suitable for binary branches and should not be nested multiple layers. Complex logic should use the traditional if-elif-else structure to ensure readability.