[Java知识库]新版Spring Boot（6）- Spring Boot 整合 Web 开发（2）

1 @ControllerAdvice

• 全局异常处理
• 全局数据绑定
• 全局数据预处理

1.1 @ControllerAdvice 全局异常处理

• 文件上传案例
  

package com.tzb.exception;


import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

/**
 * @Description 全局异常处理
 * @Author tzb
 * @Date 2021/8/15 10:54
 * @Version 1.0
 **/

@RestControllerAdvice
public class MyGlobalException {

    @ExceptionHandler(Exception.class)
    public String customException(Exception e) {
        return e.getMessage();
    }

}

1.2 全局数据绑定

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ModelAttribute;

import java.util.HashMap;
import java.util.Map;

/**
 * @Description 全局数据绑定
 * @Author tzb
 * @Date 2021/8/15 11:08
 * @Version 1.0
 **/
@ControllerAdvice
public class MyGlobalData {

    @ModelAttribute(name = "info")
    public Map<String,String> mydata(){
        Map<String,String> info = new HashMap<>();
        info.put("name", "Mike");
        info.put("address","ShangHai");
        return info;
    }
}

@RestController
public class HelloController {

    @GetMapping("/hello")
    public void hello(Model model ){
        Map<String, Object> asMap = model.asMap();
        Map<String, String> info = (Map<String, String>)asMap.get("info");
        System.out.println(info);

    }
}

1.3 请求参数预处理

@ControllerAdvice
public class MyGlobalData {

    @ModelAttribute(name = "info")
    public Map<String,String> mydata(){
        Map<String,String> info = new HashMap<>();
        info.put("name", "Mike");
        info.put("address","ShangHai");
        return info;
    }

    @InitBinder("b")
    public void b(WebDataBinder binder){
        binder.setFieldDefaultPrefix("b.");
    }

    @InitBinder("a")
    public void a(WebDataBinder binder){
        binder.setFieldDefaultPrefix("a.");
    }
}

@RestController
public class BookController {

    @PostMapping("/book")
    public void addBook(@ModelAttribute("b") Book book, @ModelAttribute("a") Author author) {
        System.out.println("book:" + book);
        System.out.println("author:" + author);
    }
}

2 异常页面定义

2.1 直接根据错误码定义页面

2.2 异常处理原理

2.3 自定义异常

2.3.1 自定义数据

package com.tzb.exception;

import org.springframework.boot.web.error.ErrorAttributeOptions;
import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.WebRequest;

import java.util.Map;

/**
 * @Description TODO
 * @Author tzb
 * @Date 2021/8/15 16:53
 * @Version 1.0
 **/
@Component
public class MyErrorAttribute extends DefaultErrorAttributes {

    @Override
    public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) {

        Map<String, Object> map = super.getErrorAttributes(webRequest, options);

        if ((Integer) map.get("status") == 404) {
            map.put("message", "页面不存在");
        }

        return map;
    }
}

2.3.2 自定义视图

package com.tzb.exception;

import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.servlet.error.DefaultErrorViewResolver;
import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Map;

/**
 * @Description TODO
 * @Author tzb
 * @Date 2021/8/15 16:59
 * @Version 1.0
 **/
@Component
public class MyErrorViewResolver extends DefaultErrorViewResolver {
    public MyErrorViewResolver(ApplicationContext applicationContext, ResourceProperties resourceProperties) {
        super(applicationContext, resourceProperties);
    }

    @Override
    public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status, Map<String, Object> model) {
        Map<String, Object> map = new HashMap<>();
        map.putAll(model);
        if((Integer)model.get("status") ==500){
            map.put("message", "服务器内部错误");
        }
        return new ModelAndView("myerror/999", map);
    }
}