Question

我正在学习Java中的Protocol Buffer。在基本序列化/反序列化之后，我试图进行压缩。在提供的代码中，我尝试使用GZIP，但在反序列化时，它会读取一条额外的记录。可以在System.out中看到一个额外的＆＃34;，＆＃34;最后。使用相同代码时不会发生此问题，但使用Snappy（在下面的代码中注释）。如果我做错了什么建议？或者，如果我可以绕过这个问题。

使用GZIP输出：

id0,NAME0
,

使用Snappy输出：

id0,NAME0

代码：

package testPkg;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import org.xerial.snappy.SnappyInputStream;
import org.xerial.snappy.SnappyOutputStream;

public class TestProtoBuf {

public static String fileNm = "C:/testFile";

public static void main(String[] args) throws IOException {
    // creating data
    List<DataClass> list = new ArrayList<>();
    for (int i = 0; i < 1; i++) {
        list.add(new DataClass("id" + i, "NAME" + i));
    }
    // writing data
    try (OutputStream os = new GZIPOutputStream(new BufferedOutputStream(new FileOutputStream(fileNm)))
    /*OutputStream os = new SnappyOutputStream(new BufferedOutputStream(new FileOutputStream(fileNm)))*/) {
        for (DataClass dc : list) {
            DataClassProtoBufProxy.DataClass.Builder bld = DataClassProtoBufProxy.DataClass.newBuilder();
            bld.setId(dc.id);
            bld.setName(dc.name);
            bld.build().writeDelimitedTo(os);
        }
        os.flush();
    }
    // reading data
    try (InputStream is = new GZIPInputStream(new BufferedInputStream(new FileInputStream(fileNm)))
    /*InputStream is = new SnappyInputStream(new BufferedInputStream(new FileInputStream(fileNm)))*/) {
        while (is.available() > 0) {
            DataClassProtoBufProxy.DataClass.Builder bld = DataClassProtoBufProxy.DataClass.newBuilder();
            bld.mergeDelimitedFrom(is);
            DataClassProtoBufProxy.DataClass dc = bld.build();
            System.out.println(dc.getId() + "," + dc.getName());
        }
    }
}

static class DataClass {
    private String id;
    private String name;

    DataClass() {
        id = null;
        name = null;
    }

    DataClass(String id, String name) {
        this.id = id;
        this.name = name;
    }
}

}

原型文件：

// [START declaration]
syntax = "proto3";
package testPkg;
// [END declaration]

// [START java_declaration]
option java_package = "testPkg";
option java_outer_classname = "DataClassProtoBufProxy";
// [END java_declaration]

// [START messages]
message DataClass {
  string id = 1;
  string name = 20;
}
// [END messages]

Maven依赖项：

<!-- https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java -->
<dependency>
    <groupId>com.google.protobuf</groupId>
    <artifactId>protobuf-java</artifactId>
    <version>3.2.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.xerial.snappy/snappy-java -->
<dependency>
    <groupId>org.xerial.snappy</groupId>
    <artifactId>snappy-java</artifactId>
    <version>1.1.2.6</version>
</dependency>

GZIP不使用Protocol Buffer。 Snappy做到了

0 个答案: