问题描述
我在Java中有一个名为“苏格兰场”的游戏。在后端，它是用Java编码的，而前端是用angular编码的。从一开始，游戏就包含枚举作为运输类型，但随后我们的任务是具有动态运输类型。因此，我们删除了枚举，并用名为Ttype的类替换了它，因为我们可以添加新的传输类型作为Ttype类的实例。我们在arraylist的帮助下做到了这一点。因此，在代码（包含许多类）中，我们替换了从枚举类型到我的新类Ttype的所有代码。它工作正常，但是尝试启动游戏时出现错误。错误很长，并说：
2020-10-29 15：25：41.901 [0; 39m [31mERROR [0; 39m [35m2596 [0; 39m [2m --- 0] 39m [2m [nio-7001-exec-2]] [ 0; 39m [36mo.accC [。[。[/]。[dispatcherServlet] [0; 39m [2m：[0; 39m] Servlet [dispatcherServlet]的Servlet.service（）在路径[]的上下文中引发异常[请求处理失败嵌套的异常是org.springframework.web.client.RestClientException：提取类型[class.se.kau.cs.sy.board.Board]和内容类型[application / json]的响应时出错；嵌套的异常是org.springframework.http.converter.HttpMessageNotReadableException：JSON解析错误：无法构造se.kau.cs.sy.board.Ttype的实例（尽管至少存在一个Creator）：无法从Object值反序列化（没有委托-或基于财产的创作者）；嵌套异常是com.fasterxml.jackson.databind.exc.MismatchedInputException：无法构造se.kau.cs.sy.board.Ttype的实例（尽管至少存在一个Creator）：无法从Object值反序列化（没有委托或属性）基于创作者） 在[来源：（pushbackinputstream）;行：1，列：139]（通过参考链：se.kau.cs.sy.board.Board [“ nodes”]-> java.util.ArrayList [0]-> se.kau.cs.sy.board .Node [“ links”]-> java.util.HashSet [0]-> se.kau.cs.sy.board.Link [“ type”]）]]的根本原因
com.fasterxml.jackson.databind.exc.MismatchedInputException：无法构造se.kau.cs.sy.board.Ttype的实例（尽管至少存在一个Creator）：无法从Object值反序列化（没有委托或属性）基于创作者） 在[来源：（pushbackinputstream）;行：1，列：139]（通过参考链：se.kau.cs.sy.board.Board [“ nodes”]-> java.util.ArrayList [0]-> se.kau.cs.sy.board .Node [“ links”]-> java.util.HashSet [0]-> se.kau.cs.sy.board.Link [“ type”]）
我不知道该怎么办，我认为错误是，现在当我没有枚举时，Ttype会引起问题。我认为这是与错误有关的类。能来吗请帮帮我。我知道可以看到很多，但是我真的不知道该怎么办。对不起，我的英语不好。希望你能理解
我的链接类：
package se.kau.cs.sy.board;
import java.io.Serializable;
public class Link implements Serializable {
private static final long serialVersionUID = 1L;
private int[] nodes = new int[2];
private Ttype type;
//Only for json deserialization
public Link() {
}
public Link(int nodea,int nodeb,Ttype t) {
nodes[0] = nodea;
nodes[1] = nodeb;
type = t;
}
public int[] getNodes() {
return nodes;
}
public Ttype getType() {
return type;
}
//Only for json deserialization
public void setNodes(int[] nodes) {
this.nodes = nodes;
}
//Only for json deserialization
public void setType(Ttype type) {
this.type = type;
}
}
我的Ttype类：
package se.kau.cs.sy.board;
import java.util.ArrayList;
import java.util.Objects;
public class Ttype{
public String Transport = "";
public Ttype(String type) {
this.Transport = type;
}
public String getTransport() {
return Transport;
}
public void setTransport(String type) {
this.Transport = type;
}
}
我的董事会课程：
package se.kau.cs.sy.board;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.UUID;
import java.util.Random;
import java.util.Scanner;
import java.io.IOException;
import se.kau.cs.sy.match.Readconfig;
import se.kau.cs.sy.util.FileHandler;
public class Board implements Serializable {
private static final long serialVersionUID = 1L;
private static Board londonBoard;
private final UUID id;
private String name = "";
private List<Node> nodes = new ArrayList<>();
static Readconfig read = new Readconfig();
static {
londonBoard = loadMap();
londonBoard.setName(read.array1[0]);
}
private Board(String name) {
id = UUID.randomUUID();
this.name = name;
}
//Only for json deserialization
public Board() {
this("");
}
public static Board create() {
return londonBoard;
}
public UUID getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Node> getNodes() {
return new ArrayList<>(nodes);
}
public Set<Link> getLinks(int node) {
return getLinks(node,null);
}
public Set<Link> getLinks(int node,Ttype type) {
Set<Link> links = nodes.get(node).getLinks();
if (type != null) {
links.removeIf(l -> l.getType() != type);
}
return links;
}
public Location getLocation(int node) {
return nodes.get(node).getLocation();
}
public Set<Integer> getNeighbourNodes(int node) {
return getNeighbourNodes(node,null); //unkNown
}
public Set<Integer> getNeighbourNodes(int node,Ttype type) {
Set<Integer> result = new HashSet<>();
Set<Link> links = this.getLinks(node,type);
for (Link l : links) {
result.add(l.getNodes()[0]);
result.add(l.getNodes()[1]);
}
result.remove(node);
return result;
}
public boolean connected(int nodeA,int nodeB,Ttype type) {
return getNeighbourNodes(nodeA,type).contains(nodeB);
}
public boolean connected(int nodeA,int nodeB) {
return getNeighbourNodes(nodeA,null ).contains(nodeB);
}
public int lastNodeIndex() {
return nodes.get(nodes.size() - 1).getId();
}
public boolean nodeExists(int number) {
return number > 0 && number <= lastNodeIndex();
}
private static Board loadMap() {
Board map = new Board();
try {
FileHandler mapHandler = new FileHandler("se/kau/cs/sy/" +read.array1[1]+".txt");
// RandomAccessFile map=new RandomAccessFile(f,"r"); //kanske bra och använda
String buffer=mapHandler.readLine();
StringTokenizer token;
token=new StringTokenizer(buffer);
int nrNodes=Integer.parseInt(token.nextToken());
Location locs[] = readMapPositions();
for (int i = 0; i < nrNodes; i++ ) {
Node newNode = new Node(i);
newNode.setLocation(locs[i]);
map.nodes.add(newNode);
}
buffer=mapHandler.readLine();
while(buffer!=null && buffer.trim().length()>0) {
token=new StringTokenizer(buffer);
int node1=Integer.parseInt(token.nextToken());
int node2=Integer.parseInt(token.nextToken());
String strType=token.nextToken();
Ttype type =null; //unkNown
for(int i = 0; i < read.typearray.size(); i++) {
if(read.typearray.get(i).Transport.equals(strType)) {
type=read.typearray.get(i); break;//ny
}
}
Link newLink = new Link(node1,node2,type);
map.nodes.get(node1).addLink(newLink);
map.nodes.get(node2).addLink(newLink);
buffer=mapHandler.readLine();
}
mapHandler.close();
}
catch(Exception e) {
e.printstacktrace();
}
return map;
}
private static Location[] readMapPositions() {
Location result[] = null;
try {
FileHandler map = new FileHandler("se/kau/cs/sy/" +read.array1[2]+ ".txt");
String buffer = map.readLine();
StringTokenizer token;
token = new StringTokenizer(buffer);
int numPos = Integer.parseInt(token.nextToken());
result = new Location[numPos];
for(int i = 0; i < numPos; i++)
{
buffer = map.readLine();
token = new StringTokenizer(buffer);
int pos = Integer.parseInt(token.nextToken());
int posX = Integer.parseInt(token.nextToken());
int posY = Integer.parseInt(token.nextToken());
result[pos] = new Location(posX,posY);
}
}
catch(Exception e) {
System.exit(1);
}
return result;
}
//Only for json deserialization
public void setNodes(List<Node> nodes) {
this.nodes = nodes;
}
}
这是一个错误。我的代码在“ MatchConfigurationImpl.Builder builder = new MatchConfigurationImpl.Builder（）;”之后崩溃。
@PostMapping("/matches")
public UUID createMatch(@RequestBody MatchConfigurationDTO conf) {
MatchConfigurationImpl.Builder builder = new MatchConfigurationImpl.Builder();
Board board = restTemplate.getForObject(integration.getBoardDetailsServiceUrl(),Board.class); //my code crashes here
if (board != null) {
builder.board(board)
.detectives(conf.getNrOfDetectives())
.startPositions(conf.getStartingPositions())
.surfacingTurns(conf.getSurfacingTurns())
.turns(conf.getNrOfTurns())
.ticketsForDetectives(conf.getTicketsdetectives()) //ny
.ticketsForMrX(conf.getTicketsMrx())
.ticketNames(conf.getTicketNames()); //ny
Match newMatch = new Match(builder.build());
//Todo: add Mr. X properly
newMatch.registerMrX(new RandomPlayer(PlayerRole.MR_X));
storage.add(newMatch,"New match");
return newMatch.getId();
}
else
return null;
}
问题可能是什么？任何想法？抱歉，如果这些类没有帮助，我会在需要时尝试添加其他类。
解决方法
错误是说Cannot construct instance of se.kau.cs.sy.board.Ttype (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator) at
似乎您应该在Jackson的Ttype类中添加一个Jackson创建者，以便在从Json反序列化时，它将知道如何创建Ttype的实例。