将 JSON Map 传递给 Spring MVC 控制器

Question

我正在尝试将 Map 的 JSON 表示形式作为 POST 参数发送到我的控制器中。

@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，所以我尝试改用 @ModelAttribute。

@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，但我意识到地图是空的。通过后来的实验，我发现任何对象（不仅仅是 HashMap）都会被实例化，但不会填写任何字段。我的类路径中确实有 Jackson，我的控制器将使用 JSON 响应。但是，我当前的配置似乎不允许 Spring 通过 GET/POST 参数读取 JSON。

如何将来自客户端 AJAX 请求的对象的 JSON 表示形式作为请求参数传递给 Spring 控制器并获取 Java 对象？

编辑添加我的相关 Spring 配置

  <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>

根据评论者的建议，我尝试了@RequestBody。只要用 双引号 引用 JSON 字符串，这将起作用。

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

这确实解决了我的直接问题，但我仍然很好奇您如何通过 AJAX 调用传入多个 JSON 对象。

Answer 1

这确实解决了我的直接问题，但我仍然很好奇您如何通过 AJAX 调用传入多个 JSON 对象。

最好的方法是拥有一个包含您要传递的两个（或多个）对象的包装器对象。然后，您将 JSON 对象构造为两个对象的数组，即

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

然后在您的控制器方法中，您将请求正文作为单个对象接收并提取两个包含的对象。即：

@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...

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;
}   

}

Answer 2

您可以使用 Jackson 库将 Json 转换为 Map。

@web-context.xml

<bean id="messageAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="messageConverters">
        <list>
            <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
        </list>
    </property>
</bean>

@maven 依赖：

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-core-lgpl</artifactId>
    <version>1.9.13</version>
</dependency>
<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-lgpl</artifactId>
    <version>1.9.13</version>
</dependency>

@控制器

@RequestMapping(value = "/method", method = RequestMethod.DELETE)
public String method(
                @RequestBody Map<String, Object> obj){

@Request（例如 jquery Ajax）

$.ajax({"type": "DELETE",
        "contentType": "application/json;",
        "url": "/method",
        "data": JSON.stringify({"key": "Ricardo"}),
        "dataType": "json";}
});

使用 Python 框架或 Play 更容易！呵呵

Answer 3

我已使用以下代码将 Map 对象传递给 Java：

Javascript 代码：

var values = {
                    "object1" : JSON.stringify(object1),
                    "object2" : JSON.stringify(object2)
            };
 var response = $http.post(url,data);

服务器端代码：

@RequestMapping(value = "/deleteData",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    public Result deleteData(@RequestBody HashMap<String, Object> dataHashMap) {
    Object1 object1=  (Object1) JsonConvertor.jsonToObject((String) dataHashMap.get("object1"), Object1.class);
        Object2 object2= (Object2) JsonConvertor.jsonToObject((String) dataHashMap.get("object2"), Object2.class);   
}

JsonConvertor 类：

public class JsonConvertor {
  public static <T> Object jsonToObject(String json, Class<T> clazz) {
    if (json == null)
      throw new IllegalArgumentException("null cannot be converted to Object");
    Gson gson = new GsonBuilder().disableHtmlEscaping().setDateFormat("dd-MMM-yyyy").create();
    return gson.fromJson(json, clazz);
  }
}

Answer 4

您没有正确获取 json。

这样做......

/*
 * Mapping for Demographics And Profiling Question Filter
 */
@RequestMapping (value = "/generalFilter")
public void ageFilteration(@RequestParam Map <String,String> filterParams,HttpServletRequest request,HttpServletResponse response) throws IOException
{
    //  System.out.println("Geographies in Controller :"+ filterParams.get("geographies"));
    List<FeasibilityBean> feasibilityList = feasibilityDao.getGeneralFeasibilityList(filterParams,request);
    //  System.out.println(" General Filter List Size:"+feasibilityList.size());
    response.getWriter().print(new Gson().toJsonTree(feasibilityList,new TypeToken<List<FeasibilityBean>>(){}.getType()));
}

}

js代码

var ages='',ageCond='',genders='',genderCond='';

    $.ajax({
        type: "POST",
        url : url,
        data : {ages:ages,ageCond:ageCond,genders:genders,genderCond:genderCond},
        beforeSend: function() { 
            $(thisVar).find('i').addClass('fa-spin');
        },
        success : function(feasibilityJson){ 

        },
        error : function(data) {
            alert(data + "error");
        },
        complete:function(){  
            $(thisVar).find('i').removeClass('fa-spin');
        }
    }); 

或者你想用json绑定bean....

https://stackoverflow.com/a/21689084/5150781 https://stackoverflow.com/a/37958883/5150781

Answer 5

    @RequestMapping(method = RequestMethod.POST)
    public HttpEntity<Resource<Customize>> customize(@RequestBody String customizeRequest) throws IOException {
       Map<String, String> map = mapper.readValue(customizeRequest, new TypeReference<Map<String,String>>(){});
       log.info("JSONX: " + customizeRequest);
       Long projectId_L = Long.parseLong(map.get("projectId"));
       [...]

Answer 6

作为@dario 的回答，但对于 Jackson 2 版本：

spring-web-context.xml

    <bean id="messageAdapter" class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
    <property name="messageConverters">
        <list>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" >
            <property name="supportedMediaTypes">    
                <list>    
                    <value>application/json;charset=utf-8</value>    
               </list>    
            </property>  
            </bean>
        </list>
    </property>
</bean>

mavenpom.xml:

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.6</version>
    </dependency>

java 控制器

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