这篇文章主要介绍了springmvc json类型转换错误解决方案,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
在用springmvc做json数据时，返回时，提示类型转换错误（http://nk.xcmnyy.com）
如下，
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org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found
for
return
value of
type
: class cn.taotao.bean.Role
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263)
Root Cause
java.lang.IllegalArgumentException: No converter found
for
return
value of
type
: class cn.taotao.bean.Role
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:187)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:174)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:81)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:113)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:854)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:765)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
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解决办法为（http://www.0834xcjl.com）
在pom中添加，只要添加上这两个jackson的支持，就可以了。
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<
dependency
>
<
groupId
>com.fasterxml.jackson.core</
groupId
>
<
artifactId
>jackson-core</
artifactId
>
<
version
>2.8.8</
version
>
</
dependency
>
<!-- 返回json字符串的支持 -->
<
dependency
>
<
groupId
>com.fasterxml.jackson.core</
groupId
>
<
artifactId
>jackson-databind</
artifactId
>
<
version
>2.8.8</
version
>
</
dependency
>
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在springmvc的controller的方法为，如下（http://3g.0834jlnk.com）
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@RequestMapping
(
"/getRole/{id}"
)
@ResponseBody
public
Role getRole(
@PathVariable
(
"id"
) Integer id ) {
Role roleById = roleService.getRoleById(id);
return
roleById;
}
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若仍不能解决，可以在springmvc配置文件中进行如下配置(待验证)
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<
mvc:annotation-driven
> <
mvc:message-converters
> <
bean
class
=
"org.springframework.http.converter.StringHttpMessageConverter"
/>
<
bean
class
=
"org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"
/>
</
mvc:message-converters
>
</
mvc:annotation-driven
>
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