SSM框架搭建系列(二)--No converter found for return value of type

墨蓝 2022-05-31 00:25 137阅读 0赞

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# 背景介绍 #

SSM框架整合Dubbo搭完之后 要测试一条完整的线,从数据库查回数据后报错找到到可转换的类型XXXentity,心想,mapper对应到实体我用了别名(typeAliasesPackage),怀疑是自己别名没写对,就将mapper的返回类型写了全路径,但是依旧报错!最终检查发现service层引入了json的相关包,但是web层没有引入。

# 问题 #

type Exception report
    
    message No converter found for return value of type: class com.zh.ssm.manager.entity.SysUser
    
    description The server encountered an internal error that prevented it from fulfilling this request.
    
    exception
    
    org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class com.zh.ssm.manager.entity.SysUser
    	org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:221)
    	org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:182)
    	org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82)
    	org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:119)
    	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:871)
    	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:777)
    	org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:870)
    	javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
    	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

# 解决方案 #

在web层的pom.xml文件中添加json相关的引用

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

# 总结 #

认真搭一遍框架会发现很多好玩的东西,有些内容只是去看是完全体会不到的。同样,也只有遇到各种各样的问题我们才能更茁壮地成长。

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