Required request parameter ‘xx‘ for method parameter type Integer is present but converted to null

1、问题

请求接口失败，查看日志出现WARN：Required request parameter 'xx' for method parameter type Integer is present but converted to null

问题是出在与前端交互层Controller

原代码：

@GetMapping("/page")
public PageBean page(@RequestParam(name = "name") String name,
                       @RequestParam(name = "xx") Integer xx,
                       @RequestParam(name = "xx1") Integer xx1,
                       @RequestParam(name = "page", defaultValue = "1") Integer page,
                       @RequestParam(name = "pageSize", defaultValue = "5") Integer pageSize) {
        PageBean pageBean = studentService.page(name, xx, xx1, page, pageSize);
        return pageBean;
    }

2、解决方案

核心原因是：‌前端传递了参数 xx，但其值为空字符串（""）或无法转换为 Integer，代码中 @RequestParam 默认要求该参数必须存在且有效

解决方案：允许参数为null，即在@RequestParam中加个属性 required = false

@GetMapping("/page")
public PageBean page(@RequestParam(name = "name", required = false) String name,
                       @RequestParam(name = "xx", required = false) Integer xx,
                       @RequestParam(name = "xx1", required = false) Integer xx1,
                       @RequestParam(name = "page", defaultValue = "1") Integer page,
                       @RequestParam(name = "pageSize", defaultValue = "5") Integer pageSize) {
        PageBean pageBean = studentService.page(name, xx, xx1, page, pageSize);
        return pageBean;
    }