使用 Redis 和 Java 进行数据库缓存 - DZone 数据库

return(list);

}

@Override

public String load( String key )

{

PreparedStatement preparedStatement = conn.prepareStatement( "SELECT name FROM student where id = ?" );

try {

preparedStatement.setString( 1, key );

ResultSet result = preparedStatement.executeQuery();

if ( result.next() )

{

return(result.getString( 1 ) );

}

return(null);

} finally {

preparedStatement.close();

}

}

}

配置使用案例：

MapOptions<K, V> options = MapOptions.< K, V > defaults()

.loader( mapLoader );

RMap<K, V> map = redisson.getMap( "test", options );

/* or */

RMapCache<K, V> map = redisson.getMapCache( "test", options );

/* or with boost up to 45x times */

RLocalCachedMap<K, V> map = redisson.getLocalCachedMap( "test", options );

/* or with boost up to 45x times */

RLocalCachedMapCache<K, V> map = redisson.getLocalCachedMapCache( "test", options );

Redis 中的直写缓存

下面是一个 Java 示例，说明如何在 Redis 中使用 Redis 中的 Redis 使用直写缓存。

在 MapWriter 对象更新缓存和数据库之前，缓存更新方法不会返回：

MapWriter<String, String> mapWriter = new MapWriter<String, String>()

{

@Override

public void writeAll( Map<String, String> map )

{

PreparedStatement preparedStatement = conn.prepareStatement( "INSERT INTO student (id, name) values (?, ?)" );

try {

for ( Entry<String, String> entry : map.entrySet() )

{

preparedStatement.setString( 1, entry.getKey() );

preparedStatement.setString( 2, entry.getValue() );

preparedStatement.addBatch();

}

preparedStatement.executeBatch();

} finally {

preparedStatement.close();

}

}

@Override

public void write( String key, String value )

{

PreparedStatement preparedStatement = conn.prepareStatement( "INSERT INTO student (id, name) values (?, ?)" );

try {

preparedStatement.setString( 1, key );

preparedStatement.setString( 2, value );

preparedStatement.executeUpdate();

} finally {

preparedStatement.close();

}

}

@Override

public void deleteAll( Collection<String> keys )

{

PreparedStatement preparedStatement = conn.prepareStatement( "DELETE FROM student where id = ?" );

try {

for ( String key : keys )

{

preparedStatement.setString( 1, key );

preparedStatement.addBatch();

}

preparedStatement.executeBatch();

} finally {

preparedStatement.close();

}

}

@Override

public void delete( String key )

{

PreparedStatement preparedStatement = conn.prepareStatement( "DELETE FROM student where id = ?" );

try {

preparedStatement.setString( 1, key );

preparedStatement.executeUpdate();

} finally {

preparedStatement.close();

}

}

}

使用配置案例：

MapOptions<K, V> options = MapOptions.< K, V > defaults()

.writer( mapWriter )

.writeMode( WriteMode.WRITE_THROUGH );

RMap<K, V> map = redisson.getMap( "test", options );

/* or */

RMapCache<K, V> map = redisson.getMapCache( "test", options );

/* or with boost up to 45x times */

RLocalCachedMap<K, V> map = redisson.getLocalCachedMap( "test", options );

/* or with boost up to 45x times */

RLocalCachedMapCache<K, V> map = redisson.getLocalCachedMapCache( "test", options );

Redis 中的后写缓存

MapWriter 接口还用于异步提交对 Map 对象（缓存）和外部存储（数据库）的更新。后台写入操作执行中使用的线程数量通过 writeBehindThreads 设置设置。

下面，我们看到 Redisson 中基于 Redis 的后写缓存实现的配置的 Java 示例：

MapOptions<K, V> options = MapOptions.< K, V > defaults()

.writer( mapWriter )

.writeMode( WriteMode.WRITE_BEHIND )

.writeBehindThreads( 8 );

RMap<K, V> map = redisson.getMap( "test", options );

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/* or */

RMapCache<K, V> map = redisson.getMapCache( "test", options );

/* or with boost up to 45x times */

RLocalCachedMap<K, V> map = redisson.getLocalCachedMap( "test", options );