将JSON映射传递到Spring MVC Controller [英] Passing JSON Map into Spring MVC Controller

问题描述

我正在尝试将地图的JSON表示作为POST参数发送到我的控制器中.

I'm trying to send a JSON representation of a Map into my controller as a POST parameter.

@RequestMapping(value = "/search.do", method = RequestMethod.GET, consumes = { "application/json" })
public @ResponseBody Results search(@RequestParam("filters") HashMap<String,String> filters, HttpServletRequest request) {
       //do stuff
}

我发现@RequestParam只会抛出500错误，因此我尝试使用@ModelAttribute.

I found that @RequestParam would just throw a 500 error, so I tried using @ModelAttribute instead.

@RequestMapping(value = "/search.do", method = RequestMethod.GET, consumes = { "application/json" })
public @ResponseBody Results search(@ModelAttribute("filters") HashMap<String,String> filters, HttpServletRequest request) {
       //do stuff
}

这将正确响应请求，但是我意识到Map是空的.在以后的实验中，我发现将实例化任何对象(不仅是HashMap)，而且不会填充任何字段.我的类路径中确实有Jackson，并且我的控制器将使用JSON进行响应.但是，似乎我的当前配置不允许Spring通过GET/POST参数读取JSON.

This would correctly respond to requests, but I realized that the Map was empty. With later experimentation, I found that any object (not just HashMap) would be instantiated, but no fields would be filled in. I do have Jackson on my classpath, and my controllers will respond with JSON. However, it would appear that my current configuration is not allowing Spring to read JSON in via a GET/POST parameter.

如何将对象的JSON表示形式从客户端AJAX请求传递给Spring控制器作为请求参数，并获取Java对象?

How does one pass JSON representations of objects from a client-side AJAX request to a Spring controller as a request parameter and get a Java object out?

编辑，添加我的相关Spring配置

EDIT Adding my relevant Spring configuration

  <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
    <property name="mediaTypes">
      <map>
        <entry key="html" value="text/html" />
        <entry key="json" value="application/json" />
      </map>
    </property>
    <property name="viewResolvers">
      <list>
        <bean class="org.springframework.web.servlet.view.UrlBasedViewResolver">
          <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
          <property name="prefix" value="/WEB-INF/jsp/" />
          <property name="suffix" value=".jsp" />
        </bean>
      </list>
    </property>
    <property name="defaultViews">
      <list>
        <bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView">
          <property name="prefixJson" value="true" />
        </bean>
      </list>
    </property>
  </bean>
  <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="messageConverters">
      <list>
        <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"/>
      </list>
    </property>
  </bean>

在评论者的建议下，我尝试了@RequestBody.只要JSON字符串用双引号加引号，就可以使用.

On the suggestion of a commenter, I tried @RequestBody. This will work, so long as the JSON strings are quoted with double quotes.

@RequestMapping(value = "/search.do", method = RequestMethod.POST, consumes = { "application/json" })
public @ResponseBody Results<T> search(@RequestBody HashMap<String,String> filters, HttpServletRequest request) {
      //do stuff
}

这确实解决了我眼前的问题，但我仍然对ou如何通过AJAX调用传递多个JSON对象感到好奇.

This does solve my immediate issue, but I'm still curious as to how ou might pass in multiple JSON objects via an AJAX call.

推荐答案

这确实解决了我眼前的问题，但我仍然对ou如何通过AJAX调用传递多个JSON对象感到好奇.

This does solve my immediate issue, but I'm still curious as to how ou might pass in multiple JSON objects via an AJAX call.

执行此操作的最佳方法是使包装器对象包含要传递的两个(或多个)对象.然后，您将JSON对象构造为两个对象的数组，即

The best way to do this is to have a wrapper object that contains the two (or multiple) objects you want to pass. You then construct your JSON object as an array of the two objects i.e.

[
  {
    "name" : "object1",
    "prop1" : "foo",
    "prop2" : "bar"
  },
  {
    "name" : "object2",
    "prop1" : "hello",
    "prop2" : "world"
  }
]

然后在控制器方法中将请求正文作为一个对象接收，并提取两个包含的对象.即:

Then in your controller method you recieve the request body as a single object and extract the two contained objects. i.e:

@RequestMapping(value="/handlePost", method = RequestMethod.POST, 
                consumes = {      "application/json" })
public void doPost(@RequestBody WrapperObject wrapperObj) { 
     Object obj1 = wrapperObj.getObj1;
     Object obj2 = wrapperObj.getObj2;

     //Do what you want with the objects...


}

包装对象看起来像...

The wrapper object would look something like...

public class WrapperObject {    
private Object obj1;
private Object obj2;

public Object getObj1() {
    return obj1;
}
public void setObj1(Object obj1) {
    this.obj1 = obj1;
}
public Object getObj2() {
    return obj2;
}
public void setObj2(Object obj2) {
    this.obj2 = obj2;
}   

}

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