SpringMVC之ajax异步交互

Springmvc默认用MappingJackson2HttpMessageConverter对json数据进行转换，需要加入jackson的包；同时使用 <mvc:annotation-driven />

@RequestBody

该注解用于Controller的方法的形参声明，当使用ajax提交并指定contentType为json形式时，通过HttpMessageConverter接口转换为对应的POJO对象。

		<dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.0</version>
        </dependency>

<script src="${pageContext.request.contextPath}/js/jquery-3.5.1.js"></script>
<%--ajax异步交互--%>
<button id="btn1">ajax异步提交</button>
<script>
    $("#btn1").click(function () {
        let url = '${pageContext.request.contextPath}/ajaxRequest';
        let data = '[{"id":1,"username":"张三"},{"id":1,"username":"李四"}]';
        $.ajax({
            type:'POST',
            url:url,
            data:data,
            contentType:'application/json;charset=utf-8',
            success:function (resp) {
                alert(JSON.stringify(resp));
            }
        })
    })
</script>

@RequestMapping("/ajaxRequest")
public void ajaxRequest(@RequestBody List<User> list){
    System.out.println(list);
}

	<!--配置处理器映射器及处理器适配器-->
    <!--此标签进行了功能增强：支持json的读写-->
    <mvc:annotation-driven></mvc:annotation-driven>

@ResponseBody

该注解用于将Controller的方法返回的对象，通过HttpMessageConverter接口转换为指定格式的数据如：json,xml等，通过Response响应给客户端。

@RequestMapping("/ajaxRequest")
@ResponseBody
public List<User> ajaxRequest(@RequestBody List<User> list){
    System.out.println(list);
    return list;
}