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[英]Convert JSONObject to List<JSONObject> or a String to List<JSONObject>
[英]exception while convert string to jsonobject
我的servlet中有一個字符串,格式如下。
{
"name": "Jam",
"noOfBooksRequired": "2",
"type": "Type 1",
"bookName": [
"The Magic",
"The Power"
]
}
其中bookName
是一個數組。 我想訪問數組中的值並在Bean中填充。 但是,當我嘗試將字符串轉換為jsonobject時,出現以下異常,因為bookName是一個數組com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected a string but was BEGIN_ARRAY
這就是我要嘗試的方式做吧
JSONObject js= new JSONObject();
String inputData= request.getParameter("inputData");
HashMap<String, String> hmap= new HashMap<String, String>();
Type type = new TypeToken<HashMap<String, String>>(){}.getType();
hmap = gson.fromJson(inputData, type);
js.putAll(hmap);
我正在做的是,將字符串轉換為映射,然后將其添加到JSONObject。
由於存在許多json序列化程序,因此不確定哪個是最好的。 現在,我有net.sf.json.JSONObject
和com.google.gson.JsonObject
有人可以幫我解決這個問題。
提前致謝
您可以將JSON映射到POJO。
如果這本書除了名稱之外還將具有更多屬性,則您將需要兩個POJO,如下所示。
這本書的POJO:
class Book {
private String name;
private String author;
public Book() {
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
還有一個書架的POJO,其中包含書籍清單:
class Shelf {
private String name;
private Integer noOfBooksRequired;
private String type;
private List<Book> books;
public Shelf() {
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getNoOfBooksRequired() {
return noOfBooksRequired;
}
public void setNoOfBooksRequired(Integer noOfBooksRequired) {
this.noOfBooksRequired = noOfBooksRequired;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public List<Book> getBooks() {
return books;
}
public void setBooks(List<Book> books) {
this.books = books;
}
}
您的JSON將如下所示:
{
"name": "Jam",
"noOfBooksRequired": "2",
"type": "Type 1",
"books": [
{"name": "The Magic", "author": "John Doe"},
{"name": "The Power", "author": "Jane Doe"}
]
}
然后,您可以使用Gson解析JSON:
Gson gson = new Gson();
Shelf shelf = gson.fromJson(inputData, Shelf.class);
考慮到您的JSON看起來像這樣(這本書可以表示為String
):
{
"name": "Jam",
"noOfBooksRequired": "2",
"type": "Type 1",
"books": [
"The Magic",
"The Power"
]
}
僅一個帶有String
列表的POJO就足夠了:
class Shelf {
private String name;
private Integer noOfBooksRequired;
private String type;
private List<String> books;
public Shelf() {
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getNoOfBooksRequired() {
return noOfBooksRequired;
}
public void setNoOfBooksRequired(Integer noOfBooksRequired) {
this.noOfBooksRequired = noOfBooksRequired;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public List<String> getBooks() {
return books;
}
public void setBooks(List<String> books) {
this.books = books;
}
}
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