在发送GET请求时出错，但在POST上工作

Question

我有一个REST链接到一个Java应用程序，该应用程序使用JDBC连接到数据库，我目前正在通过Swagger进行测试。

发送post请求完全正常，当给定类型的表为空时发送GET请求似乎也返回一个正常的响应，但是一旦在表中有数据时发送GET请求，则会得到以下错误。

GET /api/user 500 Server Error
java.lang.reflect.UndeclaredThrowableException: null
    at jdk.proxy2/jdk.proxy2.$Proxy16.getPersons(Unknown Source)
    at module.PersonModule.lambda$new$41b6884b$1(PersonModule.java:23)
    at io.jooby.internal.handler.DefaultHandler.apply(DefaultHandler.java:23)
    at io.jooby.internal.handler.WorkerHandler.lambda$apply$0(WorkerHandler.java:23)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.NoSuchMethodException: no such constructor: domain.Person.<init>()void/newInvokeSpecial
    at java.base/java.lang.invoke.MemberName.makeAccessException(MemberName.java:974)
    at java.base/java.lang.invoke.MemberName$Factory.resolveOrFail(MemberName.java:1117)
    at java.base/java.lang.invoke.MethodHandles$Lookup.resolveOrFail(MethodHandles.java:3649)
    at java.base/java.lang.invoke.MethodHandles$Lookup.findConstructor(MethodHandles.java:2750)
    at org.jdbi.v3.core.mapper.reflect.internal.BeanPropertiesFactory$BeanPojoProperties$PropertiesHolder.<init>(BeanPropertiesFactory.java:202)
    at org.jdbi.v3.core.config.JdbiCaches.lambda$declare$0(JdbiCaches.java:49)
    at org.jdbi.v3.core.config.JdbiCaches$1.lambda$get$1(JdbiCaches.java:63)
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
    at org.jdbi.v3.core.config.JdbiCaches$1.get(JdbiCaches.java:63)
    at org.jdbi.v3.core.mapper.reflect.internal.BeanPropertiesFactory$BeanPojoProperties.getProperties(BeanPropertiesFactory.java:81)
    at org.jdbi.v3.core.mapper.reflect.internal.PojoMapper.specialize0(PojoMapper.java:99)
    at org.jdbi.v3.core.mapper.reflect.internal.PojoMapper.specialize(PojoMapper.java:80)
    at org.jdbi.v3.core.result.ResultSetResultIterator.<init>(ResultSetResultIterator.java:38)
    at org.jdbi.v3.core.result.ResultIterable.lambda$of$0(ResultIterable.java:54)
    at org.jdbi.v3.core.result.ResultIterable.stream(ResultIterable.java:228)
    at org.jdbi.v3.core.result.ResultIterable.collect(ResultIterable.java:284)
    at org.jdbi.v3.sqlobject.statement.internal.ResultReturner$CollectedResultReturner.mappedResult(ResultReturner.java:275)
    at org.jdbi.v3.sqlobject.statement.internal.SqlQueryHandler.lambda$configureReturner$0(SqlQueryHandler.java:61)
    at org.jdbi.v3.sqlobject.statement.internal.CustomizingStatementHandler.invoke(CustomizingStatementHandler.java:178)
    at org.jdbi.v3.sqlobject.statement.internal.SqlQueryHandler.invoke(SqlQueryHandler.java:27)
    at org.jdbi.v3.sqlobject.internal.SqlObjectInitData$1.lambda$invoke$0(SqlObjectInitData.java:132)
    at org.jdbi.v3.core.internal.Invocations.invokeWith(Invocations.java:44)
    at org.jdbi.v3.core.internal.Invocations.invokeWith(Invocations.java:26)
    at org.jdbi.v3.core.LazyHandleSupplier.lambda$invokeInContext$1(LazyHandleSupplier.java:77)
    at org.jdbi.v3.core.internal.Invocations.invokeWith(Invocations.java:44)
    at org.jdbi.v3.core.internal.Invocations.invokeWith(Invocations.java:26)
    at org.jdbi.v3.core.LazyHandleSupplier.invokeInContext(LazyHandleSupplier.java:76)
    at org.jdbi.v3.sqlobject.internal.SqlObjectInitData$1.call(SqlObjectInitData.java:138)
    at org.jdbi.v3.sqlobject.internal.SqlObjectInitData$1.invoke(SqlObjectInitData.java:132)
    at org.jdbi.v3.sqlobject.SqlObjectFactory.lambda$attach$2(SqlObjectFactory.java:110)
    at org.jdbi.v3.core.internal.OnDemandExtensions.lambda$invoke$5(OnDemandExtensions.java:98)
    at org.jdbi.v3.core.internal.exceptions.Unchecked.lambda$function$4(Unchecked.java:76)
    at org.jdbi.v3.core.internal.OnDemandExtensions.invoke(OnDemandExtensions.java:98)
    at org.jdbi.v3.core.internal.OnDemandExtensions.lambda$createProxy$2(OnDemandExtensions.java:82)
    at org.jdbi.v3.core.Jdbi.callWithExtension(Jdbi.java:476)
    at org.jdbi.v3.core.Jdbi.withExtension(Jdbi.java:463)
    at org.jdbi.v3.core.internal.OnDemandExtensions.lambda$createProxy$3(OnDemandExtensions.java:82)
    ... 8 common frames omitted
Caused by: java.lang.NoSuchMethodError: domain.Person: method 'void <init>()' not found
    at java.base/java.lang.invoke.MethodHandleNatives.resolve(Native Method)
    at java.base/java.lang.invoke.MemberName$Factory.resolve(MemberName.java:1085)
    at java.base/java.lang.invoke.MemberName$Factory.resolveOrFail(MemberName.java:1114)
    ... 43 common frames omitted

PersonModule的第23行被声明为抛出错误，它有以下代码

 public PersonModule(PersonDAO dao){
        
        path("/api/user", () -> {
            get("", ctx -> {
                return dao.getPersons();
            });
            
            post("", ctx -> {
                Person person = ctx.body().to(Person.class);
                if (dao.getPerson(person.getEmail()) == null) {
                    dao.savePerson(person);
                    return ctx.send(StatusCode.CREATED);
                } else {
                    return ctx
                            .setResponseCode(StatusCode.UNPROCESSABLE_ENTITY)
                            .render(new ErrorMessage("That email already exists in the system"));
                }
            });
        });

return dao.getPersons()为第23行

用于获取人员的JDBI代码是

    @Override
    @SqlQuery("SELECT * FROM PERSON ORDER BY EMAIL")
    @RegisterBeanMapper(Person.class)
    public Collection<Person> getPersons();

Person.class有以下代码(还包括普通的getter和setter方法)

 public Person(Integer personID, String email, String password, String firstName, String lastName, String phone, String mobile, String industry, String bio, String city, Boolean active, String findOut, String role, String notes) {
        this.personID = personID;
        this.email = email;
        this.password = password;
        this.firstName = firstName;
        this.lastName = lastName;
        this.phone = phone;
        this.mobile = mobile;
        this.industry = industry;
        this.bio = bio;
        this.city = city;
        this.active = active;
        this.findOut = findOut;
        this.role = role;
        this.notes = notes;
    }

能帮我找出问题所在吗？

备注：GET请求在稍早的时候进行了测试，并且似乎运行良好，即使数据库中的数据也是如此。DAO的单元测试也通过，没有错误。

Answer 1

我发现了这个问题，

我域类中的构造函数似乎是错误，我在当前的Person.class中添加了一个空的构造函数来修正这个错误

public Person(){
        
    }

public Person(Integer personID, String email, String password, String firstName, String lastName, String phone, String mobile, String industry, String bio, Boolean active, String city,  String findOut, String role, String notes) {
        this.personID = personID;
        this.email = email;
        this.password = password;
        this.firstName = firstName;
        this.lastName = lastName;
        this.phone = phone;
        this.mobile = mobile;
        this.industry = industry;
        this.bio = bio;
        this.city = city;
        this.active = active;
        this.findOut = findOut;
        this.role = role;
    }

现在它很好用。如果有人能解释这是为什么，我很想知道:)

Answer 2

尝试SQL查询中的实际列名。而不是这样：

SELECT * FROM PERSON ORDER BY EMAIL

试试这个：

SELECT PERSONID, EMAIL, PASSWORD,... FROM PERSON ORDER BY EMAIL

Answer 3

您应该从错误输出中获得本质。

它与构造函数INIT中的lambda代码相关，没有这样的方法getPersons。

有了这个问题，代码应该有一个异常包装或添加到构造函数声明开始，至少对于get请求代码，例如抛出ServletException和UnavailableException。

GET /api/user 500 Server Error
java.lang.reflect.UndeclaredThrowableException: null
    at jdk.proxy2/jdk.proxy2.$Proxy16.getPersons(Unknown Source)
    at module.PersonModule.lambda$new$41b6884b$1(PersonModule.java:23)

    path("/api/user", () -> {
                get("", ctx -> {
                    return dao.getPersons();
                });

下面的操作引用了使用getPersons方法将所有人员都放到Collection对象上的奇怪操作，但是除了返回它之外，您什么也不做--我猜想它是" ctx “，不幸的是，您并没有说对象ctx的类型是什么。

@Override
@SqlQuery("SELECT * FROM PERSON ORDER BY EMAIL")
@RegisterBeanMapper(Person.class)
public Collection<Person> getPersons();

不知怎么的，Person类的所有必需构造函数参数都是在一篇文章中发送的，但是在get中没有人类是在代码中创建的，我发现奇怪的是，它没有继续抛出错误，不管您是否给它一个抽象类的无参数构造函数，但不知道它是否被视为抽象类，更正常的方法是生成DTO数据传输对象模板和

在DAO数据访问对象类之间的实体，具有要调用的接口。而且，getPersons集合似乎没有任何用处，所以为什么要进行大规模的查询检索。