解析Json双引号的问题

Question

I am using Gson to convert a json to java object. Here is the Gson

{
    "assetClassDetails":[{}],
    "assetClassRequired":null,
    "baseUnitofMeasure":"PMI",
    "bomParent":"Yes",
    "commodityCodeTaric":"84158200",
    "enLanguageKey":"EN",
    "enMaterialLongText":"Lenovo Privacy Filter for 14" Notebooks ( L, T and X1 Carbon)"",
    "grossWeightInKg":null,
    "height":null,
    "heightLengthWidthUnit":null,
    "length":null,"manufacturerPartNumber":"",
    "materialLongDescription":"Lenovo Privacy Filter for 14" Notebooks ( L, T and X1 Carbon)"",
    "physicalCategory":"Physical",
    "volume":null,
    "volumeUnit":null,
    "width":null,
    "xxLanguageKey":null,
    "xxMaterialLongText":null
 }

Problem is with the attributes enMaterialLongText & materialLongDescription. Inside value they have quotation marks.Gson fails to parse json. My code is

Gson gson = new Gson();
OperationalInfo outout = gson.fromJson(inputJson, OperationalInfo.class);

OperationalInfo class is like this:

public class OperationalInfo {

private String commodityCodeTaric= null;  //  fETCH FROM db

private String physicalCategory= null; 
private String materialType= null; // ZN01 *
private String productHierarchy= null; // Gnp Hierarchy
private String baseUnitofMeasure= null; // From Database
private String height= null; // Manual enetered
private String length= null; // Manual enetered
private String width= null; // Manual enetered
private String heightLengthWidthUnit= null; // Manual enetered
private String volume= null; // Manual enetered
private String volumeUnit= null; // Manual enetered
private String grossWeightInKg= null; // Manual enetered
private String itemCategoryGroup= null;
private String manufacturerPartNumber= null; // is same as spn
private String bomParent= null;  // yes/No    
private String materialLongDescription= null; // Manual enetered
private String enLanguageKey= null; // EN
private String enMaterialLongText= null; // materialLongDescription
private String xxLanguageKey= null;   //  EN
private String xxMaterialLongText= null;      
private String catalogueGroup = null;
private String pirStatus = null;  // Changed, Add , mark for Delete
private List<AssetClassLedger> assetClassDetails = null;
private Boolean assetClassRequired = null;
...
}

I have tried String.replace() on input json to replace double quotation mark with "\".

Update: Pl refer my following code:

Gson gson = new Gson();
String test = "{\"assetClassRequired\":\"\",\"baseUnitofMeasure\":\"PMI\",\"bomParent\":\"Yes\",\"commodityCodeTaric\":\"84158200\",\"enLanguageKey\":\"EN\",\"enMaterialLongText\":\"Lenovo Privacy Filter for 14\\\" Notebooks ( L, T and X1 Carbon)\\\"\",\"grossWeightInKg\":\"\",\"height\":\"\",\"heightLengthWidthUnit\":\"\",\"length\":\"\",\"manufacturerPartNumber\":\"\",\"materialLongDescription\":\"Lenovo Privacy Filter for 14\\\" Notebooks ( L, T and X1 Carbon)\\\"\",\"physicalCategory\":\"Physical\",\"volume\":\"\",\"volumeUnit\":\"\",\"width\":\"\",\"xxLanguageKey\":\"\",\"xxMaterialLongText\":\"\"}";
JsonReader reader1 = new JsonReader(new StringReader(test));
reader1.setLenient(true);
OperationalInfo operationalInfo = gson.fromJson(reader1, OperationalInfo.class);

Pl see that I have used 3 back-slashes for enMaterialLongText & materialLongDescription for 14 inch. But programmatically how will I know which quotation mark to escape by triple-backslash & which one to single-backslash?

Answer 1

Since your JSON is invalid, I would contact the source of the JSON to get a valid JSON. But if you really have no other way to get a valid JSON, you can try to edit the JSON beforehand to make it approximately valid. But since you can't know what the JSON looks like correctly, I strongly advise you not to use this method.

/**
 * This method tries to escape incorrect quotes. To do this, it looks at which character comes
 * after a quote character, because it assumes that a closed quote character is followed by either
 * a ",", ":", or "\n". However, if none of the characters follows, the quotation mark is
 * escaped.
 * <br />
 * Example Input:
 * <pre>
 *   { "hello": "world " test "", "number": 0 }
 * </pre>
 * Example Output:
 * <pre>
 *   { "hello": "world \" test \"", "number": 0 }
 * </pre>
 *
 * @param json The invalid JSON input
 * @return (Hopefully) correct JSON
 */
private static String tryFixJson(String json) {
  final StringBuilder resp = new StringBuilder();
  final char[] chars = json.toCharArray();
  boolean open = false;
  for (int i = 0; i < chars.length; i++) {
    final char c = chars[i];
    if (c == '"') {
      if (!open) {
        if (i != 0 && chars[i - 1] != '\\') {
          open = true;
        }
      } else if (i != chars.length - 1) {
        if (chars[i - 1] != '\\') {
          final char n = chars[i + 1];
          if (n != ',' && n != ':' && n != '\n') {
            resp.append('\\');
          } else {
            open = false;
          }
        }
      }
    }
    resp.append(c);
  }
  return resp.toString();
}

Answer 2

It fails because you need to escape special characters like " and \ . Just add a backslash before the special character and you'll be fine:

{
  "enMaterialLongText": "Lenovo Privacy Filter for 14\" Notebooks ( L, T and X1 Carbon)\""
}

Same goes for materialLongDescription .