[英]Gson conversion to a Java Pojo make values null
我必须使用休眠在数据库中保留POJO类社区。 我在类ManageCommunity中有此方法:
public void persistCommunity(String name,String domain,String idCustomer){
Session session = sessionFactory.getCurrentSession();
session.beginTransaction();
Community aCommunity=new Community();
aCommunity.setName(name);
aCommunity.setDomain(domain);
aCommunity.setIdCustomer(idCustomer);
// aCommunity.setIdCommunity(aCommunity.getIdCommunity());
session.save(aCommunity);
session.getTransaction().commit();
}
在带有doPost的servlet上,我调用此方法,然后传递由postman发送的json参数:
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
Gson g = new Gson();
System.out.println(CommunityHome.getBody(req));
Community community = g.fromJson(CommunityHome.getBody(req), Community.class);
System.out.println("Community: "+community);
HttpSession session = req.getSession(true);
try {
ManageCommunity manageCommunity = new ManageCommunity();
manageCommunity.persistCommunity(community.getName(),community.getDomain(),community.getIdCustomer());
} catch (Exception e) {
e.printStackTrace();
}
}
现在community的值是null,但是如果我看到getBody(req),就会发现json
这是getBody:
private static String getBody(HttpServletRequest request) throws IOException {
String body = null;
StringBuilder stringBuilder = new StringBuilder();
BufferedReader bufferedReader = null;
try {
InputStream inputStream = request.getInputStream();
if (inputStream != null) {
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
char[] charBuffer = new char[128];
int bytesRead = -1;
while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
stringBuilder.append(charBuffer, 0, bytesRead);
}
} else {
stringBuilder.append("");
}
} catch (IOException ex) {
throw ex;
} /*finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException ex) {
throw ex;
}
}
}*/
body = stringBuilder.toString();
return body;
}
这是POJO类:
public class Community{
public Community(){
UUID uuid=UUID.randomUUID();
String random=uuid.toString();
this.idCommunity=random;
}
public String getIdCommunity() {
return idCommunity;
}
public void setIdCommunity(String idCommunity) {
this.idCommunity = idCommunity;
}
public String getIdCustomer() {
return idCustomer;
}
public void setIdCustomer(String idCustomer) {
this.idCustomer = idCustomer;
}
public String getDomain() {
return domain;
}
public void setDomain(String domain) {
this.domain = domain;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private String idCommunity;
private String idCustomer;
private String domain;
private String name;
}
CommunityHome.getBody(req)
的内容为:
{"idCustomer":"bb05ee35-0494-49e3-9e40-38d5dae10668", "name":"VenditaAbiti2", "domain":"Commerce2"}
将您的json更改为此:
{"IdCustomer":"bb05ee35-0494-49e3-9e40-38d5dae10668",
"Name":"VenditaAbiti2",
"Domain":"Commerce2"
}
在这个小例子中可以正常工作:
String json = "{\"IdCustomer\":\"bb05ee35-0494-49e3-9e40-38d5dae10668\",\"Name\":\"VenditaAbiti2\",\"Domain\":\"Commerce2\"}";
Gson g = new Gson();
Community community = g.fromJson(json, Community.class);
System.out.println("Community:" + community.toString());
}
class Community {
@SerializedName("IdCustomer")
private String idCustomer;
@SerializedName("Name")
private String name;
@SerializedName("Domain")
private String domain;
@Override
public String toString() {
return "Community [idCustomer=" + idCustomer + ", name=" + name + ", domain=" + domain + "]";
}
//getter setter
输出: Community:Community [IdCustomer=bb05ee35-0494-49e3-9e40-38d5dae10668, Name=VenditaAbiti2, Domain=Commerce2]
编辑1:
您的Pojo变量名称应与json字符串的键名匹配。 表示JSON键"IdCustomer"
以大写字母开头。 您的变量以小写字母开头。 这不能匹配。 但是您可以像我的答案一样注释变量。 在那里,您可以给出json键的显式名称 。
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