如何自動將Spring Form數據解析為JSON對象？ （Spring，jQuery，AJAX，JSON）

Question

我有一個通過Ajax提交的春季表格。 這是我的表格

<form:form action="addToCart" method="POST"
                modelAttribute="cartProduct">
                <form:input type="hidden" path="product.productId"
                    value="${inventory.getProduct().getProductId()}" />
                <div class="card-block" style="overflow: hidden; padding: 2%">
                    <h5 style="white-space: nowrap">
                        <a href="#" class="text-primary card-title">${inventory.getProduct().getName()}</a>
                    </h5>
                    <p class="card-text text-danger">&#8369;
                        ${inventory.getProduct().getPrice()}</p>
                    <p>
                    <div class="success-message-container">
                        <span class="text-success add-to-cart"><strong>&nbsp;</strong></span>
                    </div>
                    <div class="success-message vertical-center"
                        style="display: none;">
                        <span class="text-success add-to-cart"><strong>Added
                                to cart!</strong></span>
                    </div>
                    <form:button id="addToCart" class="btn btn-block btn-warning">Add to cart</form:button>
                    <a id="viewCart" href="viewCart" class="btn btn-block btn-warning" style="display: none;">View cart</a>
                </div>
</form:form>

然后通過ajax代碼提交...

$(document).ready(function() {

var form = $("form");
var url = form.attr("action");
var formMethod = form.attr("method");

form.submit(function(event) {

    event.preventDefault();

    var thisForm = this;

    $.ajax({

        url : url,
        data : $(this).serialize(),
        type : "POST",
        headers: { 
            'Content-Type': 'application/json' 
        },
        success : function(cartProduct) {
            $(thisForm).find('.success-message-container').remove();
            $(thisForm).find('.success-message').show();
            $(thisForm).find('#addToCart').hide();
            $(thisForm).find('#viewCart').toggle();
        }
    });
});

});
});

這是接收休息控制器...

@RequestMapping(value="/addToCart", method = RequestMethod.POST)
public CartProduct addToCart(@RequestBody CartProduct cartProduct, HttpServletRequest request){

    System.out.println(cartProduct.getProduct().getProductId());
    return null;
}

但是，我不斷收到此錯誤...

POST http://localhost:8080/tommystore/customer/addToCart 400 (Bad Request)

我已經導入了Jackson以進行自動對象映射，但是它仍然無法正常工作...

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.6.3</version>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.6.3</version>
    </dependency>

我怎樣才能解決這個問題？

Answer 1

Spring使用HttpMessageConverter將請求主體轉換為方法參數。 有兩種格式（json或xml，我更喜歡json）HttpMessageConverter負責從HTTP請求消息轉換為對象以及從對象轉換為HTTP響應主體。 使用HttpMessageConverter時，應將dataType: 'xml'或添加到ajax並將數據格式更改為xml

在服務器中，配置XML Converter以將xml數據轉換為對象

@Configuration
@ComponentScan({ "yourpackage" })
public class WebConfig extends WebMvcConfigurerAdapter 
{
@Override
public void configureMessageConverters(
  List<HttpMessageConverter<?>> converters) {

    messageConverters.add(createXmlHttpMessageConverter());
    messageConverters.add(new MappingJackson2HttpMessageConverter());

    super.configureMessageConverters(converters);
}
private HttpMessageConverter<Object> createXmlHttpMessageConverter() {
    MarshallingHttpMessageConverter xmlConverter = 
      new MarshallingHttpMessageConverter();

    XStreamMarshaller xstreamMarshaller = new XStreamMarshaller();
    xmlConverter.setMarshaller(xstreamMarshaller);
    xmlConverter.setUnmarshaller(xstreamMarshaller);

    return xmlConverter;
}
}

在您的XML上下文中，注冊您的轉換器

<context:component-scan base-package="your package" />

<mvc:annotation-driven>
    <mvc:message-converters>
       <bean
         class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>

       <bean class="org.springframework.http.converter.xml.MarshallingHttpMessageConverter">
           <property name="marshaller" ref="xstreamMarshaller" />
           <property name="unmarshaller" ref="xstreamMarshaller" />
       </bean> 
    </mvc:message-converters>
</mvc:annotation-driven>

<bean id="xstreamMarshaller" class="com.fasterxml.jackson.core" />