How to use Disk Lru Cache in the Java library to improve cache efficiency
How to use Disk Lru Cache in the Java library to improve cache efficiency
Brief introduction
Caches is a common optimization technology to improve the performance and efficiency of access data.In Java, Disk Lru Cache (recently used cache) is a commonly used library that can store data on the disk and manage the cache size through the LRU algorithm.This article will introduce how to use DISK LRU CACHE in the Java library to enhance the cache efficiency and provide some Java code examples.
1. Introduce Disk Lru Cache Library
To start using Disk Lru Cache, you need to add related dependencies.In the Maven project, the following dependencies can be added to the pom.xml file:
<dependency>
<groupId>com.jakewharton</groupId>
<artifactId>disklrucache</artifactId>
<version>2.0.2</version>
</dependency>
Then use the `Import` statement to import the relevant class:
import com.jakewharton.disklrucache.DiskLruCache;
2. Initialize DISK LRU CACHE
Next, initialize the Disk Lru Cache object in the Java class.Initialization can be performed in the constructor or class initialization method.
private static final long MAX_CACHE_SIZE = 10 * 1024 * 1024; // 10 MB
private static final int VERSION = 1;
private static final int VALUE_COUNT = 1;
private static final int APP_VERSION = 1;
private static final String CACHE_DIR = "cache_directory";
private DiskLruCache cache;
public void initCache() throws IOException {
File cacheDir = new File(CACHE_DIR);
if (!cacheDir.exists()) {
cacheDir.mkdirs();
}
cache = DiskLruCache.open(cacheDir, APP_VERSION, VALUE_COUNT, MAX_CACHE_SIZE);
}
The above code will create a directory called `Cache_directory`, and initialize a cache with a maximum size of 10MB.
3. Storage data to cache
Once the cache is initialized, the data can be stored into the cache.Generally, the key value of the cache is composed of a unique key and a corresponding value.
public void putDataToCache(String key, String value) throws IOException {
DiskLruCache.Editor editor = cache.edit(key);
OutputStream outputStream = editor.newOutputStream(0);
outputStream.write(value.getBytes());
outputStream.close();
editor.commit();
}
The above code stores the `Value` of the string type into the cache, and submits to the change through the` Commit () `method.Note that the `Getbytes ()` method is used here to convert the string to byte flow.
4. Read data from the cache
When you need to read the data from the cache, you can use the corresponding key to get the value.If there is a corresponding key value pair in the cache, the corresponding value is returned.
public String getDataFromCache(String key) throws IOException {
DiskLruCache.Snapshot snapshot = cache.get(key);
if (snapshot != null) {
InputStream inputStream = snapshot.getInputStream(0);
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder builder = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
reader.close();
snapshot.close();
return builder.toString();
}
return null;
}
The above code will return the string data corresponding to the given key. If there is no corresponding key value pair in the cache, return the `null`.
5. Remove the cache data
Sometimes you need to remove a key value pair from the cache. You can use the `Remove () method to delete the cache item of the specified key.
public void removeDataFromCache(String key) throws IOException {
cache.remove(key);
}
The above code removes the cache item that matches the given key from the cache.
6. Close the cache
When you no longer need to use the cache, you can turn off the cache and release related resources through the `Close ()" method.
public void closeCache() throws IOException {
cache.close();
}
The above code will turn off the cache and release related resources.
Summarize
This article introduces the method of using Disk Lru Cache in the Java library to improve cache efficiency.First of all, we introduced the Disk Lru Cache library and initialized the cache.We then demonstrated how to store data, read data, and remove data.Finally, we discussed how to close the cache.By using Disk Lru Cache, the performance and efficiency of our applications can be improved.
Reference Code:
[GitHub - DiskLruCache](https://github.com/JakeWharton/DiskLruCache)
