Question

我有一个对象是＆＃39; Level＆＃39;对象和我测试用Spring Boot Rest Controller以两种方式传输它们：

使用JSON，在Rest Controller中我使用类似的东西：

 @RequestMapping(value = "/api/v1/layers/{layername}", method =         RequestMethod.GET, produces = "application/json")
 public @ResponseBody List<Level>  query(@PathVariable String layername,
               @RequestParam("northEastLat") Float northEastLat,
               @RequestParam("northEastLng") Float northEastLng,
               @RequestParam("northWestLat") Float northWestLat,
               @RequestParam("northWestLng") Float northWestLng,

               @RequestParam("southEastLat") Float southEastLat,
               @RequestParam("southEastLng") Float southEastLng,
               @RequestParam("southWestLat") Float southWestLat,
               @RequestParam("southWestLng") Float southWestLng
) {

List<Level> poligons=levelService.obtainLevels(layername,southWestLng,southWestLat,northWestLng,northWestLat,northEastLng,northEastLat,southEastLng,southEastLat);
int i=1;
for (Level p : poligons) {

    System.out.println("poligon" + i++ + " is:" + p.toString());
}

return poligons;
}

使用Protostuff Protobuf格式，我使用类似的东西：

  @RequestMapping(value = "/api/v1/layers/{layername}", method = RequestMethod.GET,produces = "text/plain")
  public String query(@PathVariable String layername,
                @RequestParam("northEastLat") Float northEastLat,
                @RequestParam("northEastLng") Float northEastLng,
                @RequestParam("northWestLat") Float northWestLat,
                @RequestParam("northWestLng") Float northWestLng,

                @RequestParam("southEastLat") Float southEastLat,
                @RequestParam("southEastLng") Float southEastLng,
                @RequestParam("southWestLat") Float southWestLat,
                @RequestParam("southWestLng") Float southWestLng
  ) {


List<Level> poligons=levelService.obtainLevels(layername,southWestLng,southWestLat,northWestLng,northWestLat,northEastLng,northEastLat,southEastLng,southEastLat);
LevelList list = new LevelList(poligons);

byte[] bytes;

int i=1;
for (Level p : poligons) {

    System.out.println("poligon" + i++ + " is:" + p.toString());
}

Schema<LevelList> schema = RuntimeSchema.getSchema(LevelList.class);
LinkedBuffer buffer = LinkedBuffer.allocate();



try
{
    bytes = ProtostuffIOUtil.toByteArray(list, schema, buffer);
}
finally
{
    buffer.clear();
}

 return new String(bytes);
}

Level对象格式为： [{＆＃34; wkb_geometry＆＃34;：＆＃34; {＆＃34;类型＆＃34;：＆＃34;多边形＆＃34;＆＃34;坐标＆＃34;：[[[24.446822,45.34997] [24.706508,45.352485]]]}＆＃34;＆＃34; ID＆＃34; 199＆＃34;电平＆＃34;：＆＃34; 3＆＃34;＆＃34;类型＆＃34 ;日期null}

Level对象是：

@Entity(name = "Level")
@Table(name="Level2G")
@SecondaryTables({
    @SecondaryTable(name="Level3G"),
    @SecondaryTable(name="Level4G")
})
public class Level implements Serializable {

private static final long serialVersionUID = 1L;

// @Column(name = "wkb_geometry",columnDefinition="Geometry")
//@Type(type = "org.hibernate.spatial.GeometryType")
@Column(name="wkb_geometry")
private /*Geometry */ String  wkb_geometry;

@Id
@Column(name="id")
private Integer id;


@Column(name="level")
private String level;

@Transient
private String type;

public Level() {
}

public Level(String  wkb_geometry, Integer id, String level) {
    this.wkb_geometry = wkb_geometry;
    this.id = id;
    this.level = level;
    this.type = "Feature";
}

public Level(String  wkb_geometry, Integer id, String level, String type) {
    this.wkb_geometry = wkb_geometry;
    this.id = id;
    this.level = level;
    this.type = type;
}

public Object getWkb_geometry() {
    return wkb_geometry;
}

public void setWkb_geometry(String  wkb_geometry) {
    this.wkb_geometry = wkb_geometry;
}

public Integer getId() {
    return id;
}

public void setId(Integer id) {
    this.id = id;
}

public String getLevel() {
    return level;
}

public void setLevel(String level) {
    this.level = level;
}

public String getType() {
    return type;
}

public void setType(String type) {
    this.type = type;
}

@Override
public String toString() {
    return "Level{" +
            "wkb_geometry=" + wkb_geometry +
            ", id=" + id +
            ", level='" + level + '\'' +
            ", type='" + type + '\'' +
            '}';
}
 }

LevelList对象只是Level对象列表

问题是，使用Protostuff，与JSON（3.7kb）相比，我获得了更大的有效载荷（26 kb）。为什么呢？

对于第二个选项，我也尝试设置＆＃34; application / octet-stream＆＃34;直接返回字节但仍然是相同的结果。我还比较了JSON和protobuf的速度; protobuf具有更好的性能，即使有更大的有效载荷。知道为什么吗？

Answer 1

Protostuff和Protobuf不是一回事。 Protostuff是一个包装库，可以使用许多不同的序列化格式。它还支持您似乎正在使用的运行时模式生成。该运行时架构需要发送额外的元数据以及消息，以告知接收者消息的架构。我猜你所看到的大型消息主要来自这个运行时架构数据。

使用标准的Protobuf，架构不会随消息一起发送，因为假设发件人和收件人已经就编译到两个程序中的.proto文件提供的架构达成一致。如果您使用带有标准.proto文件的Protobuf，您会发现它生成的消息比JSON小得多。

Answer 2

您的测试中至少有一个问题。

从字节数组到String的转换无效：

bytes = ProtostuffIOUtil.toByteArray(list, schema, buffer);
return new String(bytes);

String的构造函数将尝试将字节数组解析为UTF-8字符串（最可能;取决于您的语言环境设置），但根据定义给定的数据不是有效的UTF-8字符串。

如果您想进行更好的尺寸比较，您应该以下列形式编写测试：

LevelList source = testData();
byte[] jsonData = generateJson(source);
byte[] protobufData = generateProtobuf(source);
System.out.println("JSON=" + jsonData.size() + " Protobuf=" + protobufData.size());

这里的要点是让你的测试可以重现，以便其他人可以重复它。

protobuf有效载荷大于JSON？

2 个答案: