jooq java.lang.CastException:java.lang.String不能强制转换为java.lan

Question

在一个项目中，我使用jklingsporn vertx-jooq作为jooq CodeGenerator来创建vertxified DAO和POJOS作为async。我有一个生成的ContractDao.java类

import io.vertx.core.Future;
import io.github.jklingsporn.vertx.jooq.classic.async.AsyncClassicQueryExecutor;
/**
* This class is generated by jOOQ.
*/
@Generated(value = { "http://www.jooq.org", "jOOQ version:3.10.6" }, comments = "This class is generated by jOOQ")
@SuppressWarnings({ "all", "unchecked", "rawtypes" })
public class ContractDao extends AbstractAsyncVertxDAO<ContractRecord, jooq.tables.pojos.Contract, Long, Future<List<jooq.tables.pojos.Contract>>, Future<jooq.tables.pojos.Contract>, Future<Integer>, Future<Long>> implements io.github.jklingsporn.vertx.jooq.classic.VertxDAO<ContractRecord, jooq.tables.pojos.Contract, Long> {
/**
* @param configuration
*            Used for rendering, so only SQLDialect must be set and must be one
*            of the MYSQL types or POSTGRES.
* @param delegate
*            A configured AsyncSQLClient that is used for query execution
*/
public ContractDao(Configuration configuration, io.vertx.ext.asyncsql.AsyncSQLClient delegate) {
super(Contract.CONTRACT, jooq.tables.pojos.Contract.class, new AsyncClassicQueryExecutor<ContractRecord, jooq.tables.pojos.Contract, Long>(configuration, delegate, jooq.tables.pojos.Contract::new, Contract.CONTRACT));
}
....
}

它使用生成的Contract.java pojo类和BigDecimal字段。

/**
* This class is generated by jOOQ.
*/
@Generated(
value = {
"http://www.jooq.org",
"jOOQ version:3.10.6"
},
comments = "This class is generated by jOOQ"
)
@SuppressWarnings({ "all", "unchecked", "rawtypes" })
public class Contract implements VertxPojo, IContract {
...
private BigDecimal costValue;
...
}

然后在vert.x Verticle类中，我有一个方法fetchContracts:

private void fetchContracts(final Message<Void> msg) {
contractDao.findAll().setHandler(arContracts -> {
...
});
}

到目前为止，它工作得很好，但如果我在表合同字段costValue中有一个数值，当我调用fetchContracts方法时，我会得到一个异常

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Number

我想是某种数据类型不匹配。我已经看到，如果我理解正确的话，这可以通过数据类型强制或强制转换来解决，如下所述：casting org.jooq.TableField<长>至org.jooq.TableField<BigDecimal>

但在这种特殊情况下，我不清楚应该在哪里以及如何进行选角。

我试过类似的东西：

private void fetchContracts(final Message<Void> msg) {
jooq.tables.Contract.CONTRACT.COST_VALUE.coerce(String.class);
contractDao.findAll().setHandler(arContracts -> {
...
});
}

但它不起作用。知道吗？提前谢谢。

编辑：

我添加堆栈跟踪：

[ERROR] 2018-08-07 09:42:54,368: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Number ( de.bfft.licencemgmt.server.UserVerticle.lambda$100(UserVerticle.java:998)) [vert.x-eventloop-thread-1]  []
[ERROR] 2018-08-07 09:42:54,368: (RECIPIENT_FAILURE,500) java.lang.String cannot be cast to java.lang.Number ( de.bfft.licencemgmt.client.viewslogic.agreements.AgreementsViewLogic.lambda$6(AgreementsViewLogic.java:61)) [vert.x-eventloop-thread-4]  []
[ERROR] 2018-08-07 09:42:54,368: Failed to handleMessage. address: 1 ( io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:228)) [vert.x-eventloop-thread-4]  []
java.lang.NullPointerException: null
at com.vaadin.server.AbstractExtension.extend(AbstractExtension.java:77) ~[vaadin-server-8.4.4.jar:8.4.4]
at com.vaadin.ui.Notification.show(Notification.java:502) ~[vaadin-server-8.4.4.jar:8.4.4]
at de.bfft.licencemgmt.client.viewslogic.agreements.AgreementsViewLogic.lambda$0(AgreementsViewLogic.java:39) ~[classes/:?]
at io.vertx.core.impl.FutureImpl.tryFail(FutureImpl.java:165) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.impl.FutureImpl.fail(FutureImpl.java:97) ~[vertx-core-3.5.1.jar:3.5.1]
at de.bfft.licencemgmt.client.viewslogic.agreements.AgreementsViewLogic.lambda$6(AgreementsViewLogic.java:62) ~[classes/:?]
at io.vertx.core.eventbus.impl.EventBusImpl.lambda$convertHandler$1(EventBusImpl.java:349) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:223) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:200) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:533) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:339) ~[vertx-core-3.5.1.jar:3.5.1]
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463) [netty-transport-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]
[ERROR] 2018-08-07 09:42:54,383: Unhandled exception ( io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:345)) [vert.x-eventloop-thread-4]  []
java.lang.NullPointerException: null
at com.vaadin.server.AbstractExtension.extend(AbstractExtension.java:77) ~[vaadin-server-8.4.4.jar:8.4.4]
at com.vaadin.ui.Notification.show(Notification.java:502) ~[vaadin-server-8.4.4.jar:8.4.4]
at de.bfft.licencemgmt.client.viewslogic.agreements.AgreementsViewLogic.lambda$0(AgreementsViewLogic.java:39) ~[classes/:?]
at io.vertx.core.impl.FutureImpl.tryFail(FutureImpl.java:165) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.impl.FutureImpl.fail(FutureImpl.java:97) ~[vertx-core-3.5.1.jar:3.5.1]
at de.bfft.licencemgmt.client.viewslogic.agreements.AgreementsViewLogic.lambda$6(AgreementsViewLogic.java:62) ~[classes/:?]
at io.vertx.core.eventbus.impl.EventBusImpl.lambda$convertHandler$1(EventBusImpl.java:349) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:223) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:200) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:533) ~[vertx-core-3.5.1.jar:3.5.1]
at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:339) ~[vertx-core-3.5.1.jar:3.5.1]
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463) [netty-transport-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.19.Final.jar:4.1.19.Final]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]

在UserVerticle.java类中导致异常的代码中，堆栈跟踪中的第998行对应于"log.error(arContracts.cause((("下面的第三行：

private void fetchContracts(final Message<Void> msg) {
contractDao.findAll().setHandler(arContracts -> {
if (arContracts.failed()) {
log.error(arContracts.cause());
msg.fail(500, arContracts.cause().getMessage());
return;
}
final List<Contract> contracts = arContracts.result();
log.debug("Found {} contracts", contracts.size());
final JsonArray jsonArray = new JsonArray(
contracts.stream().map(contract -> contract.toJson()).collect(Collectors.toList()));
msg.reply(jsonArray);
});
}

Answer 1

问题出在json中的十进制转换上。Json自动将十进制数转换为字符串，但它期望的是十进制数，这不知何故引发了异常

事实证明，还有一个额外的CustomVertxGenerator.java类，它为vert.x-jooq扩展了ClassicSyncVertxGenerator，并提供了一个方法，在JSON转换过程中处理从字符串到字符串的其他类型。这对我来说是新的。

当在类的方法中修复了postgresqldb中数字类型的转换时，问题就解决了。