我想将以下 JSON 字符串转换为 java 对象：
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"
}
]
}"
我的目标是轻松访问它，例如：
(e.g. MyJsonObject myobj = new MyJsonObject(jsonString)
myobj.mymusic[0].id would give me the ID, myobj.libraryname gives me "My Library").
我听说过 Jackson，但我不确定如何使用它来适应我拥有的 json 字符串，因为由于涉及“mymusic”列表，它不仅仅是键值对。我怎样才能与杰克逊一起完成这个任务，或者如果杰克逊不是最适合这个任务的人，我可以通过一些更简单的方法来完成这个任务吗？
无需为此使用 GSON； Jackson 可以做简单的地图/列表：
ObjectMapper mapper = new ObjectMapper();
Map<String,Object> map = mapper.readValue(json, Map.class);
或更方便的 JSON 树：
JsonNode rootNode = mapper.readTree(json);
顺便说一句，您没有理由不能实际创建 Java 类并更方便地执行它（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/
来自他们的网站：
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创建一个 MyType 类（当然，重命名）。当您处理数组时，如果您更喜欢手动执行所有解析（也很简单），那么它可能会变得有点复杂，请查看 http://www.json.org/ 并下载 Java 源代码Json 解析器对象。
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);
在我的例子中，我将 JSON 字符串作为列表传递。因此，当您传递列表时，请使用以下解决方案。
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>>>(){});
Gson 也很适合：http://code.google.com/p/google-gson/
” Gson 是一个 Java 库，可用于将 Java 对象转换为其 JSON 表示形式。它还可用于将 JSON 字符串转换为等效的 Java 对象。 Gson 可以处理任意 Java 对象，包括您没有源代码的现有对象。 ”
查看 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（我是的开发者）可以将json转换为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
我有问题中提到的相同类型的 JSON。
"{
"Service": "User Service",
"Work": [
{
"Name": "abc",
"Type": "xyz",
"Mamber": ["lmn", "jkl"]
}
]
}"
我正在使用Jackson（objectMapper）将字符串转换为Java对象。
使用 .class 类型的 readValue 不起作用。
readValue("JSON String", Temp.class)
对我来说最重要的词是：
readValue("JSON String", new TypeReference<Map<String, Object>>(){})
public void parseEmployeeObject() throws 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);
}
{
"schedule": {
"cron": "30 19 2 MON-FRI",
"timezone": "Europe/London",
"tradeQuery": {
"filter": [
{
"name": "bookType",
"operand": "equals",
"value": "FO"
},
{
"name": "bookType",
"operand": "equals",
"value": "FO"
}
],
"parameter": [
{
"name": "format",
"value": "CSV"
},
{
"name": "pagesize",
"value": "1000"
}
]
},
"xslt" :""
}
}
public 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 + "]";
}
public 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 + "]";
}
public 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 + "]";
}
public 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 + "]";
}
public 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 + "]";
}