注解介绍

@RequestBody 通常用于POST请求方式
@RequestParam使用参数：@RequestParam(value = "name")，但是@RequestParam注解中的value必须和前端传入参数的key一致，自动匹配。
@RequestBody和@RequestParam可以组合使用。
@RequestBody在每个方法中只能使用一次，但@RequestParam可以使用多次
@RequestBody接收的是请求体里面的数据(application/json)；@RequestParam接收的是key-value里面的参数

GET请求

单参，无注解

效果和使用@RequestParam注解一样

1	http://localhost:8080/demo/getData?name=111

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public void getData(String name){
    System.out.println(name);
}

单参，`@RequestParam`

注意：@RequestParam(value = "name")，入参必须与value属性名一致；不加value，则默认为Java方法中的接收参数名

例如：

1	@RequestParam(value = "name1") String name

1	http://localhost:8080/demo/getData?name=111

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public void getData(@RequestParam String name){
    System.out.println(name);
}

多参，无注解

效果和使用@RequestParam注解一样

1	http://localhost:8080/demo/getData?name1=111&name2=222

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public void getData(String name1, String name2){
    System.out.println(name1 + "，" + name2);
}

多参，`@RequestParam`

注意：@RequestParam(value = "name")，入参必须与value属性名一致；不加value，则默认为Java方法中的接收参数名
例如：

1 2	// 入参name1，用name接收 @RequestParam(value = "name1") String name

1	http://localhost:8080/demo/getData?name1=111&name2=222

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public void getData(@RequestParam String name1, @RequestParam String name2){
    System.out.println(name1 + "，" + name2);
}

实体，无注解

效果和使用@RequestBody注解一样

1	http://localhost:8080/demo/getData?id=1&name=zhangsan

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public DemoEntity getData(DemoEntity params){
    System.out.println(params.toString());
    return params;
}

实体，`@RequestBody`

http://localhost:8080/demo/getData

Body入参：
{
    "id":111,
    "name":"zhangsan"
}

@RequestMapping(value = "/getData", method = RequestMethod.GET)
public void getData(@RequestBody DemoEntity params){
    System.out.println(params.toString());
}

POST请求

单参，无注解

效果和使用@RequestParam注解一样

1	http://localhost:8080/demo/addData?name=111

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(String name){
    System.out.println(name);
}

单参，`@RequestParam`

注意：@RequestParam(value = "name")，入参必须与value属性名一致；不加value，则默认为Java方法中的接收参数名
例如：

1 2	// 入参name1，用name接收 @RequestParam(value = "name1") String name

1	http://localhost:8080/demo/addData?name=111

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(@RequestParam String name){
    System.out.println(name);
}

多参，无注解

效果和使用@RequestParam注解一样

1	http://localhost:8080/demo/addData?name1=111&name2=222

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(String name1, String name2){
    System.out.println(name1 + "，" + name2);
}

多参，`@RequestParam`

注意：@RequestParam(value = "name")，入参必须与value属性名一致；不加value，则默认为Java方法中的接收参数名
例如：

1 2	// 入参name1，用name接收 @RequestParam(value = "name1") String name

1	http://localhost:8080/demo/addData?name1=111&name2=222

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(@RequestParam String name1, @RequestParam String name2){
    System.out.println(name1 + "，" + name2);
}

实体，无注解

效果和使用@RequestBody注解一样

1	http://localhost:8080/demo/addData?id=111&name=zhangsan

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(DemoEntity params){
    System.out.println(params.toString());
}

实体，`@RequestBody`

@RequestMapping(value = "/addData", method = RequestMethod.POST)
public void addData(@RequestBody DemoEntity params){
    System.out.println(params.toString());
}

实体+文件，`@RequestParam`+无注解

文件和参数一起提交

    @RequestMapping("/upload")
    public void upload(@RequestParam(value = "file") MultipartFile files, DemoEntity parmas){
        // {id=111,name=zhangsan}
        System.out.println(params);
        //保存文件
        String s = UploadUtils.uploadFile(files, filePath);
    }

后端Ajax写法 ：
```JavaScript
    function submit(){
        var file = $("#img")[0].files[0];
        if (file){
            var fileSize = file.size/(1024*1024);
            if(fileSize>1){
            alert('图片大小最大不能超过1M！');
            return false;
            }
        }
        var fd = new FormData();
        fd.append("id", $("#id").val())
        fd.append("name", $("#name").val())
        fd.append("file", file)
        $.ajax({
            type: "post",
            url: "http://localhost:8080/demo/upload",
            data: fd,
            contentType: false,
            processData: false,
            success: function (data,status) { }
        })
    }