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今天在查找一个序列化和反序列化相关的问题时#xff0c;意外发现使用DataInputStream读取和ByteBuffer读取之间性能相差巨大#xff0c;本文就来记录下这两者在读取整数类型时的性能差异#xff0c;以便在平时使用的过程中引起注意
DataInputStream数据…背景
今天在查找一个序列化和反序列化相关的问题时意外发现使用DataInputStream读取和ByteBuffer读取之间性能相差巨大本文就来记录下这两者在读取整数类型时的性能差异以便在平时使用的过程中引起注意
DataInputStream数据读取 Vs ByteBuffer数据读取
我们会分别使用DataInputStream和ByteBuffer读取不同长度的字节数组分别测试读取Short,Int,Long三类整数然后分别看一下他们的性能
性能测试代码如下
package org.example.jmh.deserialize;import static java.util.concurrent.TimeUnit.MICROSECONDS;
import static org.example.jmh.deserialize.DataUtil.createByteArray;import java.io.ByteArrayInputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.infra.Blackhole;Warmup(iterations 2, time 2)
Measurement(iterations 3, time 10)
Fork(1)
OutputTimeUnit(MICROSECONDS)
public class ByteBufferVsByteArrayDataInputBenchmark {State(Scope.Benchmark)public static class ByteBufferBackedDataInputState {ByteBuffer buffer;DataInput dataInput;Param({8, 32, 64, 128})int size;byte[] data;public void createData() {this.data createByteArray(size);}Setup(Level.Trial)public void init() {createData();this.buffer ByteBuffer.wrap(data);this.dataInput new BufferDataInput(buffer);}void reset() {buffer.position(0);}}State(Scope.Benchmark)public static class StreamBackedDataInpuState {ByteArrayInputStream bis;DataInput dataInput;Param({8, 32, 64, 128})int size;byte[] data;public void createData() {this.data createByteArray(size);}Setup(Level.Trial)public void init() {createData();this.bis new ByteArrayInputStream(data);this.dataInput new DataInputStream(bis);}void reset() {bis.reset();}}Benchmarkpublic void streamBackedDataInputReadShort(StreamBackedDataInpuState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readShort());pos 2;}state.reset();}Benchmarkpublic void bufferBackedDataInputReadShort(ByteBufferBackedDataInputState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readShort());pos 2;}state.reset();}Benchmarkpublic void streamBackedDataInputReadInt(StreamBackedDataInpuState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readInt());pos 4;}state.reset();}Benchmarkpublic void bufferBackedDataInputReadInt(ByteBufferBackedDataInputState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readInt());pos 4;}state.reset();}Benchmarkpublic void streamBackedDataInputReadLong(StreamBackedDataInpuState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readLong());pos 8;}state.reset();}Benchmarkpublic void bufferBackedDataInputReadLong(ByteBufferBackedDataInputState state, Blackhole bh) throws IOException {DataInput input state.dataInput;int size state.size;int pos 0;while (pos size) {bh.consume(input.readLong());pos 8;}state.reset();}public static class BufferDataInput implements DataInput {private final ByteBuffer data;public BufferDataInput(ByteBuffer data) {this.data data;}Overridepublic void readFully(byte[] bytes) {}Overridepublic void readFully(byte[] bytes, int i, int i1) {}Overridepublic int skipBytes(int i) {data.position(data.position() i);return data.position();}Overridepublic boolean readBoolean() {return data.get() ! 0;}Overridepublic byte readByte() {return data.get();}Overridepublic int readUnsignedByte() {return data.get() 0xFF;}Overridepublic short readShort() {return data.getShort();}Overridepublic int readUnsignedShort() {return data.getShort() 0xffff;}Overridepublic char readChar() {return data.getChar();}Overridepublic int readInt() {return data.getInt();}Overridepublic long readLong() {return data.getLong();}Overridepublic float readFloat() {return data.getFloat();}Overridepublic double readDouble() {return data.getDouble();}Overridepublic String readLine() {return null;}Overridepublic String readUTF() {return null;}}}
jmh的测试结果 从结果可以看出不论是读取ShortInt还是LongByteBuffer都比DataInputStream有很大的性能优势大概3-4倍的差异那么你知道造成这种性能差距的原因是什么吗留个悬念
