MyBatis 本身并沒有提供內置的數據緩存功能,但你可以通過 MyBatis 的插件機制來實現數據緩存。以下是一個簡單的實現方法:
public interface Cache {
Object get(Object key);
void put(Object key, Object value);
void clear();
}
import java.util.HashMap;
import java.util.Map;
public class SimpleCache implements Cache {
private final Map<Object, Object> cache = new HashMap<>();
@Override
public Object get(Object key) {
return cache.get(key);
}
@Override
public void put(Object key, Object value) {
cache.put(key, value);
}
@Override
public void clear() {
cache.clear();
}
}
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.util.Properties;
@Intercepts({
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})
public class CacheInterceptor implements Interceptor {
private Cache cache = new SimpleCache();
@Override
public Object intercept(Invocation invocation) throws Throwable {
MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
Object parameter = invocation.getArgs()[1];
String sqlId = mappedStatement.getId();
// 只緩存查詢操作
if (sqlId.endsWith("select")) {
Object result = cache.get(parameter);
if (result != null) {
return result;
} else {
result = invocation.proceed();
cache.put(parameter, result);
return result;
}
} else {
// 清除緩存
cache.clear();
return invocation.proceed();
}
}
@Override
public Object plugin(Object target) {
return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties properties) {
}
}
<!-- ... -->
<plugins>
<plugin interceptor="com.example.CacheInterceptor"/>
</plugins>
<!-- ... -->
</configuration>
這樣,你就實現了一個簡單的數據緩存功能。請注意,這個示例僅適用于簡單的查詢場景,對于復雜查詢和分頁查詢等,你可能需要根據實際情況進行調整。此外,這個示例沒有考慮緩存的失效問題,你可能需要根據業務需求添加相應的失效策略。