


How to elegantly get Java entity class variable name to dynamically build MyBatis query conditions?
Dynamically building query conditions is very common when using MyBatis-Plus or other ORM frameworks for database operations. This article discusses how to elegantly obtain Java entity class variable names to avoid maintenance problems caused by hard-coded strings, especially for using the tk MyBatis framework.
Problem: When tk MyBatis builds Example object query, the conditional statement directly uses hard-coded strings (such as "isdeleted"), and the maintenance cost is high when there are many field names or changes. Developers want to get variable names directly like dog.isdeleted
, or convenient ways similar to Lombok annotations.
Solution: tk MyBatis itself does not provide a way to directly get the name of the entity class variable. The best practice is to migrate to MyBatis-Plus, leveraging its QueryChainWrapper
and LambdaQueryChainWrapper
to provide more flexible query methods. LambdaQueryChainWrapper
is particularly recommended, which allows the use of Lambda expressions to directly refer to entity class attributes, avoiding hard-coded attribute names.
Example of Lambda expression for MyBatis-Plus:
lambdaQuery().eq(Entity::getId, value).list();
This code directly references the id
attribute in Entity
class through Entity::getId
, without explicitly writing the "id" string. This simplifies the code, improves readability, and effectively solves maintenance problems. Although reflection is still used at the bottom, MyBatis-Plus' API design hides the complexity of reflection and improves development efficiency. In contrast, although it is feasible to use reflection directly, the code complexity is significantly increased and error-prone. Therefore, the Lambda expression method of MyBatis-Plus is a better solution.
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Emerging technologies pose both threats and enhancements to Java's platform independence. 1) Cloud computing and containerization technologies such as Docker enhance Java's platform independence, but need to be optimized to adapt to different cloud environments. 2) WebAssembly compiles Java code through GraalVM, extending its platform independence, but it needs to compete with other languages for performance.

Different JVM implementations can provide platform independence, but their performance is slightly different. 1. OracleHotSpot and OpenJDKJVM perform similarly in platform independence, but OpenJDK may require additional configuration. 2. IBMJ9JVM performs optimization on specific operating systems. 3. GraalVM supports multiple languages and requires additional configuration. 4. AzulZingJVM requires specific platform adjustments.

Platform independence reduces development costs and shortens development time by running the same set of code on multiple operating systems. Specifically, it is manifested as: 1. Reduce development time, only one set of code is required; 2. Reduce maintenance costs and unify the testing process; 3. Quick iteration and team collaboration to simplify the deployment process.

Java'splatformindependencefacilitatescodereusebyallowingbytecodetorunonanyplatformwithaJVM.1)Developerscanwritecodeonceforconsistentbehavioracrossplatforms.2)Maintenanceisreducedascodedoesn'tneedrewriting.3)Librariesandframeworkscanbesharedacrossproj

To solve platform-specific problems in Java applications, you can take the following steps: 1. Use Java's System class to view system properties to understand the running environment. 2. Use the File class or java.nio.file package to process file paths. 3. Load the local library according to operating system conditions. 4. Use VisualVM or JProfiler to optimize cross-platform performance. 5. Ensure that the test environment is consistent with the production environment through Docker containerization. 6. Use GitHubActions to perform automated testing on multiple platforms. These methods help to effectively solve platform-specific problems in Java applications.

The class loader ensures the consistency and compatibility of Java programs on different platforms through unified class file format, dynamic loading, parent delegation model and platform-independent bytecode, and achieves platform independence.

The code generated by the Java compiler is platform-independent, but the code that is ultimately executed is platform-specific. 1. Java source code is compiled into platform-independent bytecode. 2. The JVM converts bytecode into machine code for a specific platform, ensuring cross-platform operation but performance may be different.

Multithreading is important in modern programming because it can improve program responsiveness and resource utilization and handle complex concurrent tasks. JVM ensures the consistency and efficiency of multithreads on different operating systems through thread mapping, scheduling mechanism and synchronization lock mechanism.


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