@ControllerAdvice
1、处理全局异常
2、预设全局数据
3、请求参数预处理
1 使用upload案例 设置异常
- application.yml
spring:
servlet:
multipart:
max-file-size: 1KB
- MyCustomException
package com.thciwei.upload;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.multipart.MaxUploadSizeExceededException;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
@ControllerAdvice
public class MyCustomException {
@ExceptionHandler(MaxUploadSizeExceededException.class)
public void myexception(MaxUploadSizeExceededException e, HttpServletResponse resp) throws IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter out = resp.getWriter();
out.write("上传文件大小不能超出限制!");
out.flush();
out.close();
}
}
注意设置 text/html;charset=utf-8，使resp视图不会乱码
上传文件时，超过1KB 显示“上传文件大小不能超出限制!”
2 预设全局数据
package com.thciwei.demo;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ModelAttribute;
import java.util.HashMap;
import java.util.Map;
@ControllerAdvice
public class GlobalData {
@ModelAttribute(value = "info")
public Map<String, Object> mydata() {
Map<String, Object> map = new HashMap<>();
map.put("name", "java");
map.put("address", "www.thciwei.com");
return map;
}
}
package com.thciwei.demo;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.Map;
import java.util.Set;
@RestController
public class HelloController {
@GetMapping("/hello")
public String hello(Model model) {
Map<String, Object> map = model.asMap();
Set<String> keySet = map.keySet();
for (String key : keySet) {
System.out.println(key + ":" + map.get(key));
}
return "hello";
}
}
打印内容 info:{address=www.thciwei.com, name=java}
3 请求参数预处理
- Book
package com.thciwei.demo;
@Data
public class Book {
private String name;
private Double price;
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", price=" + price +
'}';
}
}
- Author
package com.thciwei.demo;
@Data
public class Author {
private String name;
private Integer age;
@Override
public String toString() {
return "Author{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
- BookController
package com.thciwei.demo;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class BookController {
@PostMapping("/book")
public void addBook(Book book,Author author){
System.out.println(book);
System.out.println(author);
}
}
使用 postman发送数据
后台打印
Book{name='三国演义,罗贯中', price=99.0}
Author{name='三国演义,罗贯中', age=60}
name合并了，这是很差的接口设计，如果真的出现这种问题，可以通过我们的@ControllerAdvice解决
各给他们一个value
package com.thciwei.demo;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class BookController {
@PostMapping("/book")
public void addBook(@ModelAttribute("b") Book book, @ModelAttribute("a") Author author){
System.out.println(book);
System.out.println(author);
}
}
加前缀
package com.thciwei.demo;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import java.util.HashMap;
import java.util.Map;
@ControllerAdvice
public class GlobalData {
@ModelAttribute(value = "info")
public Map<String, Object> mydata() {
Map<String, Object> map = new HashMap<>();
map.put("name", "java");
map.put("address", "www.thciwei.com");
return map;
}
@InitBinder("a")
public void initA(WebDataBinder binder){
binder.setFieldDefaultPrefix("a.");
}
@InitBinder("b")
public void initB(WebDataBinder binder){
binder.setFieldDefaultPrefix("b.");
}
}
