[英]How can I convert the following JSON string to Java Object by Gson?
[英]How to convert the following json string to java object?
我想將以下 JSON 字符串轉換為 java object:
String jsonString = "{
"libraryname": "My Library",
"mymusic": [
{
"Artist Name": "Aaron",
"Song Name": "Beautiful"
},
{
"Artist Name": "Britney",
"Song Name": "Oops I did It Again"
},
{
"Artist Name": "Britney",
"Song Name": "Stronger"
}
]
}"
我的目標是輕松訪問它,例如:
(e.g. MyJsonObject myobj = new MyJsonObject(jsonString)
myobj.mymusic[0].id would give me the ID, myobj.libraryname gives me "My Library").
我聽說過 Jackson,但我不確定如何使用它來適應 json 字符串,因為它不僅僅是鍵值對,因為涉及“mymusic”列表。 如何使用 Jackson 完成此操作,或者如果 Jackson 不是最適合此操作,是否有更簡單的方法可以完成此操作?
無需為此使用 GSON; 傑克遜可以做任何簡單的地圖/列表:
ObjectMapper mapper = new ObjectMapper();
Map<String,Object> map = mapper.readValue(json, Map.class);
或更方便的 JSON 樹:
JsonNode rootNode = mapper.readTree(json);
順便說一句,沒有理由不能實際創建 Java 類並更方便地執行它(IMO):
public class Library {
@JsonProperty("libraryname")
public String name;
@JsonProperty("mymusic")
public List<Song> songs;
}
public class Song {
@JsonProperty("Artist Name") public String artistName;
@JsonProperty("Song Name") public String songName;
}
Library lib = mapper.readValue(jsonString, Library.class);
查看 Google 的 Gson: http : //code.google.com/p/google-gson/
從他們的網站:
Gson gson = new Gson(); // Or use new GsonBuilder().create();
MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2
您只需要使用 json 字符串中的所有字段創建一個 MyType 類(當然是重命名的)。 當您處理數組時,它可能會變得更復雜一些,如果您更喜歡手動進行所有解析(也很簡單),請查看http://www.json.org/並下載 Json 的 Java 源代碼解析器對象。
Gson gson = new Gson();
JsonParser parser = new JsonParser();
JsonObject object = (JsonObject) parser.parse(response);// response will be the json String
YourPojo emp = gson.fromJson(object, YourPojo.class);
Gson 對它也有好處: http : //code.google.com/p/google-gson/
" Gson 是一個 Java 庫,可用於將 Java 對象轉換為其 JSON 表示。它還可以用於將 JSON 字符串轉換為等效的 Java 對象。Gson 可以處理任意 Java 對象,包括您所做的預先存在的對象沒有源代碼的。”
檢查 API 示例:https ://sites.google.com/site/gson/gson-user-guide#TOC-Overview更多示例: http : //www.mkyong.com/java/how-do-convert-java -object-to-from-json-format-gson-api/
Underscore-java可以將 json 轉換為 Object。
String jsonString = "{\n" +
" \"libraryname\":\"My Library\",\n" +
" \"mymusic\":[{\"Artist Name\":\"Aaron\",\"Song Name\":\"Beautiful\"},\n" +
" {\"Artist Name\":\"Britney\",\"Song Name\":\"Oops I did It Again\"},\n" +
" {\"Artist Name\":\"Britney\",\"Song Name\":\"Stronger\"}]}";
Map<String, Object> jsonObject = U.fromJsonMap(jsonString);
System.out.println(jsonObject);
// {libraryname=My Library, mymusic=[{Artist Name=Aaron, Song Name=Beautiful}, {Artist Name=Britney, Song Name=Oops I did It Again}, {Artist Name=Britney, Song Name=Stronger}]}
System.out.println(U.<String>get(jsonObject, "mymusic[0].Artist Name"));
// Aaron
Underscore-java (我是它的開發者)可以將 json 轉換為 Object。
import com.github.underscore.U;
String jsonString = "{\n" +
" \"libraryname\":\"My Library\",\n" +
" \"mymusic\":[{\"Artist Name\":\"Aaron\",\"Song Name\":\"Beautiful\"},\n" +
" {\"Artist Name\":\"Britney\",\"Song Name\":\"Oops I did It Again\"},\n" +
" {\"Artist Name\":\"Britney\",\"Song Name\":\"Stronger\"}]}";
Map<String, Object> jsonObject = U.fromJsonMap(jsonString);
System.out.println(jsonObject);
// {libraryname=My Library, mymusic=[{Artist Name=Aaron, Song Name=Beautiful}, {Artist Name=Britney, Song Name=Oops I did It Again}, {Artist Name=Britney, Song Name=Stronger}]}
System.out.println(U.<String>get(jsonObject, "mymusic[0].Artist Name"));
// Aaron
公共無效 parseEmployeeObject() 拋出 NoSuchFieldException、SecurityException、JsonParseException、JsonMappingException、IOException {
Gson gson = new Gson();
ObjectMapper mapper = new ObjectMapper();
// convert JSON string to Book object
Object obj = mapper.readValue(Paths.get("src/main/resources/file.json").toFile(), Object.class);
endpoint = this.endpointUrl;
String jsonInString = new Gson().toJson(obj);
JsonRootPojo organisation = gson.fromJson(jsonInString, JsonRootPojo.class);
for(JsonFilter jfil : organisation.getSchedule().getTradeQuery().getFilter())
{
String name = jfil.getName();
String value = jfil.getValue();
}
System.out.println(organisation);
}
{“時間表”:{“cron”:“30 19 2 MON-FRI”,“時區”:“歐洲/倫敦”,
"tradeQuery": { "filter": [ { "name": "bookType", "operand": "equals", "value": "FO" }, { "name": "bookType", "operand": "等於”,“值”:“FO”}],“參數”:[{“名稱”:“格式”,“值”:“CSV”},{“名稱”:“頁面大小”,“值”:“ 1000" } ] }, "xslt":"" }
}
公共 class JesonSchedulePojo {
public String cron;
public String timezone;
public JsonTradeQuery tradeQuery;
public String xslt;
public String getCron() {
return cron;
}
public void setCron(String cron) {
this.cron = cron;
}
public String getTimezone() {
return timezone;
}
public void setTimezone(String timezone) {
this.timezone = timezone;
}
public JsonTradeQuery getTradeQuery() {
return tradeQuery;
}
public void setTradeQuery(JsonTradeQuery tradeQuery) {
this.tradeQuery = tradeQuery;
}
public String getXslt() {
return xslt;
}
public void setXslt(String xslt) {
this.xslt = xslt;
}
@Override
public String toString() {
return "JesonSchedulePojo [cron=" + cron + ", timezone=" + timezone + ", tradeQuery=" + tradeQuery
+ ", xslt=" + xslt + "]";
}
公共 class JsonTradeQuery {
public ArrayList<JsonFilter> filter;
public ArrayList<JsonParameter> parameter;
public ArrayList<JsonFilter> getFilter() {
return filter;
}
public void setFilter(ArrayList<JsonFilter> filter) {
this.filter = filter;
}
public ArrayList<JsonParameter> getParameter() {
return parameter;
}
public void setParameter(ArrayList<JsonParameter> parameter) {
this.parameter = parameter;
}
@Override
public String toString() {
return "JsonTradeQuery [filter=" + filter + ", parameter=" + parameter + "]";
}
公共 class JsonFilter {
public String name;
public String operand;
public String value;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getOperand() {
return operand;
}
public void setOperand(String operand) {
this.operand = operand;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
@Override
public String toString() {
return "JsonFilter [name=" + name + ", operand=" + operand + ", value=" + value + "]";
}
公共 class JsonParameter {
public String name;
public String value;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
@Override
public String toString() {
return "JsonParameter [name=" + name + ", value=" + value + "]";
}
公共 class JsonRootPojo {
public JesonSchedulePojo schedule;
public JesonSchedulePojo getSchedule() {
return schedule;
}
public void setSchedule(JesonSchedulePojo schedule) {
this.schedule = schedule;
}
@Override
public String toString() {
return "JsonRootPojo [schedule=" + schedule + "]";
}
就我而言,我將 JSON 字符串作為列表傳遞。 因此,當您通過列表時,請使用以下解決方案。
ObjectMapper mapper = new ObjectMapper();
String json = "[{\"classifier\":\"M\",\"results\":[{\"opened\":false}]}]";
List<Map<String, Object>> map = mapper.readValue(json, new TypeReference<List<Map<String, Object>>>(){});
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