How to perform code optimization and performance tuning?

Code optimization and performance tuning are very important parts of software development. On the one hand, they can improve the running speed and efficiency of the program. On the other hand, they can also reduce resource consumption and improve the reliability and stability of the system. This article will bring some common code optimization and performance tuning tips.

1. Code optimization

1. Reduce the number of loops

Reducing the number of loops can reduce resource consumption and improve program efficiency. The number of loops can be reduced in the following ways:

(1) Using more efficient data structures, such as hash tables, red-black trees, etc., to replace data structures such as arrays and linked lists can reduce searches and the time complexity of sorting.

(2) Use cache to store calculation results to avoid repeated calculations, especially in calculation-intensive situations, which can greatly improve the efficiency of the program.

(3) Merging multiple loop nested codes into one loop can reduce the number of loops and improve program efficiency.

2. Use bit operations to replace multiplication and division

Bit operations can be calculated at the machine level, so they are faster and more resource-saving, and can greatly improve the efficiency of the program. You can replace some simple multiplication and division operations with bitwise operations, such as converting a * 2^n to a << n.

3. Optimize string operations

String operations are one of the common operations in development, but they tend to be lower-performance operations. The performance of string operations can be improved in the following ways:

(1) Use string splicing operations as little as possible, especially when using string splicing in loops, which will lead to frequent string allocation and Free up memory and affect the efficiency of the program.

(2) Using StringBuilder or StringBuffer instead of String type to perform string operations can reduce the number of string allocation and release memory, and greatly improve the efficiency of the program.

(3) Use the intern() method to reduce duplication of strings, especially in string comparison and judgment. intern() can merge duplicate strings in the string constant pool, thereby improving Program efficiency.

4. Optimize exception handling

Exception handling is one of the essential parts of writing Java code, but it is also one of the performance bottlenecks of some programs. You can optimize exception handling and improve program efficiency in the following ways:

(1) Try to avoid using exception handling to handle expected errors, especially using exception handling in loops. Because exception handling requires searching upwards in the stack, this consumes a lot of resources and affects the efficiency of the program.

(2) Avoid performing too many operations in the exception handling code block, which can reduce the overhead of exception handling and improve the efficiency of the program.

(3) Try to reduce the creation and destruction of objects in exception handling, because the creation and destruction of objects will also consume a lot of resources. Try to place object creation and destruction outside of exception handling code blocks.

5. Using the JIT compiler

The JIT (Just-In-Time) compiler is part of the Java virtual machine, which can dynamically compile Java code to the local machine code, thereby improving the efficiency of the program. Enabling the JIT compiler can significantly increase the speed of your program.

6. Reduce memory leaks

Memory leak is a common program problem. If there is a memory leak in the program, it will cause excessive memory usage and eventually cause the system to crash. . By tracking the memory allocation and recycling of the program, memory leaks in the program can be discovered in time, and measures can be taken to repair them to avoid the impact of memory leaks on program performance.

2. Performance tuning

1. Use cache

Using cache can reduce the number of database or other I/O operations, thereby improving program efficiency . Store hot data in the cache and try to avoid frequent changes to the data in the cache. This can reduce the number of cache updates and make better use of the cache.

2. Reduce the number of database operations

Database operations are usually one of the time bottlenecks in the program. You can reduce the number of database operations in the following ways:

(1) Use batch processing to merge multiple database operations into one operation, which can reduce the number of database connections and improve program efficiency.

(2) Use cache to cache commonly used database records in memory to avoid repeated queries and improve program efficiency.

(3) Optimizing the database, such as creating appropriate indexes, reasonably writing SQL statements, etc., can improve the query efficiency of the database.

3. Separate business logic

Separating business logic can avoid unnecessary calculations and queries, and simplify program code. Different business logic in the program can be divided into different modules according to business needs and processed separately to achieve the best performance of the program.

4. Using multi-threading

Multi-threading can improve the parallel processing capability of the program, thereby achieving higher program efficiency. Some time-consuming operations in the program can be processed using multi-threading, thereby improving the efficiency of the program.

Summarize:

Code optimization and performance tuning require specific analysis and practice based on the needs of the program and the actual situation. Through the above optimization techniques and methods, the running speed and efficiency of the program can be improved, the consumption of resources can be reduced, the reliability and stability of the system can be improved, and the overall performance of the program can be improved.

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