未找到默认构造函数；嵌套异常是 java.lang.NoSuchMethodException bean 配置

Posted 2023-04-12

【中文标题】未找到默认构造函数；嵌套异常是 java.lang.NoSuchMethodException bean 配置

【英文标题】：No default constructor found; nested exception is java.lang.NoSuchMethodException bean configuration

【发布时间】：2016-05-05 23:14:29

【问题描述】：

我正在尝试在 H2 数据库上运行一些 sql，我相信我的 sql 架构已经运行。虽然我不确定如何让数据源工作。我已经为我的数据源设置器添加了@Repository 注释和@Autowired 注释，我们将不胜感激。

package ping.repositories;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;
import ping.cascade.integration.CascadeInterface;
import ping.cascade.integration.company.CascadeFactory;
import ping.domain.Cascade;
import ping.domain.PingRequestBody;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;

@Repository
public class CascadeListRepository 

    private static final Logger log = LoggerFactory.getLogger(CascadeListRepository.class);

    private JdbcTemplate jdbcTemplate;
    private DataSource dataSource;

    private ArrayList<CascadeInterface> cascadeList;
    private PingRequestBody pingRequestBody;

    public CascadeListRepository(PingRequestBody pingRequestBody)
        this.cascadeList = new ArrayList<CascadeInterface>();
        this.pingRequestBody = pingRequestBody;
    

    @Autowired
    public void setDataSource(DataSource dataSource) 
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    

    public ArrayList<CascadeInterface> getCascadeList()

        CascadeFactory cascadeFactory = new CascadeFactory();



        jdbcTemplate.query(
                "SELECT cascade_id, cascade_name, cascade_object FROM cascade", 
                (rs, rowNum) -> new Cascade(rs.getInt("cascade_id"), rs.getString("cascade_name"), rs.getString("cascade_object"))
        ).forEach(cascade -> log.info(cascade.toString()));
        log.info("Finished sql");



        return cascadeList;
    

例外是：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cascadeListRepository' defined in URL [jar:file:/Users/charlesbryant/projects/java/spring/cb-ping-service/build/libs/cb-ping-service-0.1.0.jar!/ping/repositories/CascadeListRepository.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [ping.repositories.CascadeListRepository]: No default constructor found; nested exception is java.lang.NoSuchMethodException: ping.repositories.CascadeListRepository.<init>()
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.3.RELEASE.jar!/:1.3.3.RELEASE]
    at ping.Application.main(Application.java:10) [cb-ping-service-0.1.0.jar!/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_31]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_31]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_31]
    at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_31]
    at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:54) [cb-ping-service-0.1.0.jar!/:na]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_31]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [ping.repositories.CascadeListRepository]: No default constructor found; nested exception is java.lang.NoSuchMethodException: ping.repositories.CascadeListRepository.<init>()
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:85) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]
    ... 23 common frames omitted
Caused by: java.lang.NoSuchMethodException: ping.repositories.CascadeListRepository.<init>()
    at java.lang.Class.getConstructor0(Class.java:3074) ~[na:1.8.0_31]
    at java.lang.Class.getDeclaredConstructor(Class.java:2170) ~[na:1.8.0_31]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:80) ~[spring-beans-4.2.5.RELEASE.jar!/:4.2.5.RELEASE]

【参考方案1】：

似乎有道理。您没有定义默认构造函数。 即：

public CascadeListRepository() //No parameters makes this the default

【参考方案2】：

您不仅没有默认构造函数，而且您拥有的构造函数需要一个 PingRequestBody 但您没有自动装配它，因此 Spring 目前永远无法自动实例化此类。根据您的 Spring 应用程序上下文，您可能想要添加一个默认构造函数，即没有参数，或者将 @Autowired 添加到您现有的构造函数中。

@Autowired
public CascadeListRepository(PingRequestBody pingRequestBody)
    this.cascadeList = new ArrayList<CascadeInterface>();
    this.pingRequestBody = pingRequestBody;

@Charles Bryant，针对您在下面的评论，您为什么要在控制器中手动实例化 CascadeListRepository？你已经用@Repository 注释了它，所以它应该是你的spring应用程序上下文中的一个bean，你可以在你的控制器中简单地@Autowire。如果你手动实例化它，那么 spring 上下文不会意识到它并且无法控制它的生命周期......

【讨论】：

我实际上是从我的控制器实例化这个类，所以我发现这不会真正起作用。我不得不用数据源自动连接我的控制器，并通过构造函数传递它。我已经读过你可以通过调用应用程序上下文来访问它，我只看到你有 beans.xml 设置的例子，我没有，我不确定正确的语法/模式是什么？