com.google.gson.JsonSyntaxException when parsing simple JSON Inputstream

Question

I am getting com.google.gson.JsonSyntaxException when parsing simple JSON Inputstream

My json is this.

{ "logdata": [{ "millis": "1000", "light": "333" }, { "millis": "2000", "light": "333" } ] }

Java class -

import java.util.List;
public class Datalist {

private List<NavData> logdata;

/**
 * @return the logdata
 */
public List<NavData> getLogdata() {
    return logdata;
}

/**
 * @param logdata the logdata to set
 */
public void setLogdata(List<NavData> logdata) {
    this.logdata = logdata;
}

public class NavData {

private String millis;

private String light;

/**
 * @return the millis
 */
public String getMillis() {
    return millis;
}

/**
 * @param millis the millis to set
 */
public void setMillis(String millis) {
    this.millis = millis;
}

/**
 * @return the light
 */
public String getLight() {
    return light;
}

/**
 * @param light the light to set
 */
public void setLight(String light) {
    this.light = light;
}

}

Json Input Stream Reader Class - Whereas assetData is the inputStream of above json.

   JsonReader reader = new JsonReader(new InputStreamReader(assetData, "UTF-8"));
   Gson gson = new GsonBuilder().create();

   Datalist out = gson.fromJson(reader, Datalist.class);

   System.out.println(".."+out.getLogdata());

Answer 1

The problem is because you can't cast a list of string to a list with these items:

{
 "millis": "1000",
 "light": "333",
 "temp": "78.32",
 "vcc": "3.54"
}

If you want to cast to a list of these items, you need to create a class with these items and the property will be:

@Expose
private List<NavData> logdata;

Where NavData is a class with these parameters

import com.google.gson.annotations.Expose;
public class NavData {
  @Expose
  private String millis;
  @Expose
  private String light;

  public String getMillis() {
      return millis;
  }
  public void setMillis(String millis) {
      this.millis = millis;
  }
  public String getLight() {
      return light;
  }
  public void setLight(String light) {
      this.light = light;
  }
}

To read the inputStream :

StringBuilder stringBuilder = new StringBuilder();
CharBuffer charBuffer = CharBuffer.allocate(1024);

while (yourInputStream.read(charBuffer) > 0) {
      charBuffer.flip();
      stringBuilder.append(charBuffer.toString());
      charBuffer.clear();
}

finally :

Gson gson = new GsonBuilder().enableComplexMapKeySerialization()
    .excludeFieldsWithoutExposeAnnotation().serializeNulls().create();

Datalist result = gson.fromJson(stringBuilder.toString(), Datalist.class);