在客戶端和服務端交互使用JSON的時候,有byte[]類型的數據時候,JSON字符串會成倍增長,每個字節都會轉變成0x..的字符串 ,增加瞭數據交互的文件傳輸量。
/*
* GOSN常用類
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package org.brtx.tools;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import java.io.IOException;
import java.lang.reflect.Type;
import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
/**
*toJson的相關方法
* @author Administrator
*/
public class GSONTOOLS {
/**
* 獲取GSON轉換模式,默認日期格式為“yyyy-MM-dd HH:mm:ss”
* @return
*/
public static Gson getGson() {
GsonBuilder builder = new GsonBuilder();
// 不轉換沒有 @Expose 註解的字段
builder.excludeFieldsWithoutExposeAnnotation();
builder.registerTypeAdapter(Timestamp.class, new TimestampTypeAdapter()).setDateFormat("yyyy-MM-dd HH:mm:ss").create();
builder.registerTypeHierarchyAdapter(byte[].class, new ByteArrayTypeAdapter()).create();
Gson gson = builder.create();
return gson;
}
/**
* 獲取GSON轉換模式,設置時間格式為dataFat
* @param dataFat 時間格式
* @return
*/
public static Gson getGson(String dataFat) {
GsonBuilder builder = new GsonBuilder();
// 不轉換沒有 @Expose 註解的字段
builder.excludeFieldsWithoutExposeAnnotation();
builder.registerTypeAdapter(Timestamp.class, new TimestampTypeAdapter()).setDateFormat(dataFat).create();
builder.registerTypeHierarchyAdapter(byte[].class, new ByteArrayTypeAdapter()).create();
Gson gson = builder.create();
return gson;
}
}
/**
* json包含日期類型的時候的處理方法
* @author Administrator
*/
class TimestampTypeAdapter implements JsonSerializer<Timestamp>, JsonDeserializer<Timestamp> {
private final DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
public JsonElement serialize(Timestamp src, Type arg1, JsonSerializationContext arg2) {
String dateFormatAsString = format.format(new Date(src.getTime()));
return new JsonPrimitive(dateFormatAsString);
}
public Timestamp deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
if (!(json instanceof JsonPrimitive)) {
throw new JsonParseException("The date should be a string value");
}
try {
Date date = format.parse(json.getAsString());
return new Timestamp(date.getTime());
} catch (ParseException e) {
throw new JsonParseException(e);
}
}
}
class ByteArrayTypeAdapter implements JsonSerializer<byte[]>, JsonDeserializer<byte[]> {
public JsonElement serialize(byte[] src, Type typeOfSrc, JsonSerializationContext context) {
BASE64Encoder encode = new BASE64Encoder();
String base64 = encode.encode(src);
return new JsonPrimitive(base64);
}
public byte[] deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
if (!(json instanceof JsonPrimitive)) {
throw new JsonParseException("The date should be a string value");
}
try {
BASE64Decoder decode = new BASE64Decoder();
byte[] base64 = decode.decodeBuffer(json.getAsString());
return base64;
} catch (IOException ex) {
}
return null;
}
}
使用這個類將byte[]通過base64進行壓縮,降低JSON的數據量4倍左右。
摘自 狐貍愛上貓—-JAVA LINUX SWING EXTJS AJAX專欄