带rest的SpringMVC无法将对象转换为json

erhoui1w  于 2021-07-23  发布在  Java
关注(0)|答案(1)|浏览(352)

我有一个springmvc应用程序,我已经向它添加了restweb服务。因此,用户可以使用视图与请求和响应进行通信,而应用程序可以使用rest并使用json使用req和resp。
web应用程序部分工作正常,问题是其余部分不工作。下面是初始化器类

public class WebAppInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
        appContext.register(WebMvcConfig.class);

        ServletRegistration.Dynamic dispatcher = servletContext.addServlet(
                "SpringDispatcher", new DispatcherServlet(appContext));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");

    }
}

web部件工作正常,但调用rest时出现错误:

<h1>HTTP Status 500 – Internal Server Error</h1>
<hr class="line" />
<p><b>Type</b> Exception Report</p>
<p><b>Message</b> No converter found for return value of type: class java.util.ArrayList</p>
<p><b>Description</b> The server encountered an unexpected condition that prevented it from fulfilling the request.
</p>
<p><b>Exception</b></p>
<pre>org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class java.util.ArrayList
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:224)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:181)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:123)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
javax.servlet.http.HttpServlet.service(HttpServlet.java:626)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

我在maven pom中添加了jackson依赖项

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.11.3</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.11.3</version>
    </dependency>

我的dto类(从rest请求返回)拥有使用lombok的所有getter和setter
请帮助了解需要什么额外的配置才能使其余部分正常工作。

bjp0bcyl

bjp0bcyl1#

解决了我忘记在配置类上添加注解@enablewebmvc的问题。这允许一组默认转换器。
添加注解后,一切正常

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