Question

我试图序列化这个对象（OperatorDTO），所以我可以使用RPC将它从我的服务器端发送到客户端。我已经阅读了有关此主题的其他帖子，但我不知道为什么我做的事情与其他人不同。

当我正在运行我的项目时，会发生此错误

Compiling module edu.example.RPCExample
         Computing all possible rebind results for 'edu.example.client.service.ExampleService'
            Rebinding edu.example.client.service.ExampleService
               Invoking generator com.google.gwt.user.rebind.rpc.ServiceInterfaceProxyGenerator
                  Generating client proxy for remote service interface 'edu.example.client.service.ExampleService'
                     [ERROR] 'edu.example.client.models.OperatorDTO' has no instantiable subtypes
         [ERROR] Errors in 'edu/example/client/service/ExampleServiceClientImpl.java'
            [ERROR] Line 18: Failed to resolve 'edu.example.client.service.ExampleService' via deferred binding
         Unification traversed 16362 fields and methods and 1526 types. 1494 are considered part of the current module and 1494 had all of their fields and methods traversed.
      [ERROR] Compiler returned false
      [WARN] recompile failed
      [WARN] continuing to serve previous version

我不明白为什么会收到错误＆＃34; OperatorDTO没有可实例化的子类型＆＃34;当我实现了io.serializable并且只在类中使用基本数据类型时。在序列化时，是否有我在课堂上使用的东西？

package edu.example.client.models;
import java.io.Serializable;

public final class OperatorDTO implements Serializable
{   
    private static final long serialVersionUID = 1L;
    private final int ID_MINIMUM_VALUE = 11;
    private final int ID_MAXIMUM_VALUE = 99;
    private final int RANK_MINIMUM_VALUE = -1;
    private final int RANK_MAXIMUM_VALUE = 1;
    private final int NAME_MINIMUM_LENGTH = 2;
    private final int PASSWORD_MINIMUM_LENGTH = 6;
    private final int NUMBER_OF_SPECIAL_CHARACTERS = 3;

    private int oprID;
    private String oprNavn;
    private String ini;
    private String cpr;
    private String password;
    private int rank;

public OperatorDTO(int oprID, String oprNavn, String ini, String cpr, String password, int rank) {
        setOprID(oprID);
        setName(oprNavn);
        setIni(ini);
        setCpr(cpr);
        setPassword(password);
        setRank(rank);
    }

    public OperatorDTO(int oprID, String oprNavn, String ini, String cpr, String password) {
        setOprID(oprID);
        setName(oprNavn);
        setIni(ini);
        setCpr(cpr);
        setPassword(password);
    }

    public void setIni(String ini) {
        this.ini = ini;
    }

    public String getIni() {
        return this.ini;
    }

    public void setRank(int rank) {
        if(rank >= RANK_MINIMUM_VALUE && rank <= RANK_MAXIMUM_VALUE)
            this.rank = rank;kravende");
    }

    public int getRank() {
        return this.rank;
    }

    public void setOprID(int oprID) {
        if(oprID >= ID_MINIMUM_VALUE && oprID <= ID_MAXIMUM_VALUE)
            this.oprID = oprID;
    }

    public int getOprID() {
        return this.oprID;
    }

    public void setName(String name) {
        if(name != null)
            if(name.length() >= NAME_MINIMUM_LENGTH)
                this.oprNavn = name;
    }

    public void setCpr(String cpr) {
        this.cpr = cpr;
    }

    public void setPassword(String password) {
        if(valPass(password))
            this.password = password;
    }

    public String getName() {
        return this.oprNavn;
    }

    public String getCpr() {
        return this.cpr;
    }

    public String getPassword() {
        return this.password;
    }

    private boolean valPass(String pass) {
        if(pass.length() < PASSWORD_MINIMUM_LENGTH)
            return false;

        byte lowerCase = 0;
        byte upperCase = 0;
        byte digit = 0;
        byte specialChar = 0;
        char[] passChar = pass.toCharArray();

        for (char c : passChar) {
            if(Character.isLowerCase(c)) 
                lowerCase = 1;
            else if(Character.isUpperCase(c))
                upperCase = 1;
            else if(Character.isDigit(c)) 
                digit = 1;
            else if(c == 46 || c == 45 || c == 95 || c == 43 || c ==33 || c == 63 || c == 61) 
                specialChar = 1;
            else 
                return false;
        }
        return (lowerCase + upperCase + digit + specialChar) >= NUMBER_OF_SPECIAL_CHARACTERS;
    }

    @Override
    public String toString() {
        return "OperatorDTO{" + "oprID=" + oprID + ", oprNavn=" + oprNavn + ", ini=" + ini + ", cpr=" + cpr + ", password=" + password + ", rank=" + rank + '}';
    }
}

提前感谢您的帮助！

Answer 1

GWT需要默认构造函数。

请参阅http://www.gwtproject.org/doc/latest/tutorial/RPC.html#serialize

GWT序列化 - 类没有可实例化的子类型

1 个答案: