Spring Boot文档阅读笔记-exception handling–@ExceptionHandler解析与实例

谁借莪１个温暖的怀抱￠ 2022-10-17 01:44 164阅读 0赞

程序结构如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxNzg0NDI3NjE_size_16_color_FFFFFF_t_70][]

源码如下：

CustomExceptionHandler.java

package com.example.demo.controller;
    
    import com.example.demo.exception.RecordNotFoundException;
    import com.example.demo.object.ErrorResponse;
    import org.springframework.http.HttpHeaders;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.ResponseEntity;
    import org.springframework.validation.ObjectError;
    import org.springframework.web.bind.MethodArgumentNotValidException;
    import org.springframework.web.bind.annotation.ControllerAdvice;
    import org.springframework.web.bind.annotation.ExceptionHandler;
    import org.springframework.web.context.request.WebRequest;
    import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    
    @SuppressWarnings({"unchecked", "rawtypes"})
    @ControllerAdvice
    public class CustomExceptionHandler extends ResponseEntityExceptionHandler {
    
        @ExceptionHandler(Exception.class)
        public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request){
    
            List<String> details = new ArrayList<>();
            details.add(ex.getLocalizedMessage());
            ErrorResponse error = new ErrorResponse("Server Error", details);
            return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
        }
    
        @ExceptionHandler(RecordNotFoundException.class)
        public final ResponseEntity<Object> handleUserNotFoundException(RecordNotFoundException ex, WebRequest request){
    
            List<String> detail = new ArrayList<>();
            detail.add(ex.getLocalizedMessage());
            ErrorResponse error = new ErrorResponse("Record Not Found", detail);
            return new ResponseEntity<>(error, HttpStatus.NOT_FOUND);
        }
    
    
        @Override
        protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
    
            List<String> details = new ArrayList<>();
            for(ObjectError error : ex.getBindingResult().getAllErrors()){
    
                details.add(error.getDefaultMessage());
            }
    
            ErrorResponse error = new ErrorResponse("Validation Failed", details);
    
            return new ResponseEntity(error, HttpStatus.BAD_REQUEST);
        }
    }

MyController.java

package com.example.demo.controller;
    
    import com.example.demo.exception.RecordNotFoundException;
    import com.example.demo.object.EmployeeVO;
    import com.example.demo.repository.EmployeeDB;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.*;
    
    import javax.validation.Valid;
    
    @RestController
    public class MyController {
    
        @PostMapping(value = "/employees")
        public ResponseEntity<EmployeeVO> addEmployee(@Valid @RequestBody EmployeeVO employeeVO){
    
            EmployeeDB.addEmployee(employeeVO);
            return new ResponseEntity<EmployeeVO>(employeeVO, HttpStatus.OK);
        }
    
        @GetMapping(value = "/employees/{id}")
        public ResponseEntity<EmployeeVO> getEmployeeById(@PathVariable("id") Integer id){
    
            EmployeeVO employeeById = EmployeeDB.getEmployeeById(id);
            if(employeeById == null){
    
                throw new RecordNotFoundException("Invalid employee id : " + id);
            }
    
            return new ResponseEntity<EmployeeVO>(employeeById, HttpStatus.OK);
        }
    }

RecordNotFoundException.java

package com.example.demo.exception;
    
    import org.springframework.http.HttpStatus;
    import org.springframework.web.bind.annotation.ResponseStatus;
    
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public class RecordNotFoundException extends RuntimeException {
    
        public RecordNotFoundException(String exception){
    
            super(exception);
        }
    }

EmployeeVO.java

package com.example.demo.object;
    
    import javax.validation.constraints.Email;
    import javax.validation.constraints.NotEmpty;
    import javax.xml.bind.annotation.XmlAccessType;
    import javax.xml.bind.annotation.XmlAccessorType;
    import javax.xml.bind.annotation.XmlRootElement;
    import java.io.Serializable;
    
    @XmlRootElement(name = "employee")
    @XmlAccessorType(XmlAccessType.FIELD)
    public class EmployeeVO implements Serializable {
    
        private static final long serialVersionUID = 1L;
    
        private Integer employeeId;
    
        @NotEmpty(message = "first name must not be empty")
        private String firstName;
    
        @NotEmpty(message = "last name must not be empty")
        private String lastName;
    
        @NotEmpty(message = "email must not be empty")
        @Email(message = "email should be a valid email")
        private String email;
    
        public EmployeeVO(Integer employeeId, String firstName, String lastName, String email) {
    
            super();
            this.employeeId = employeeId;
            this.firstName = firstName;
            this.lastName = lastName;
            this.email = email;
        }
    
        public EmployeeVO() {
        }
    
        public Integer getEmployeeId() {
            return employeeId;
        }
    
        public void setEmployeeId(Integer employeeId) {
            this.employeeId = employeeId;
        }
    
        public String getFirstName() {
            return firstName;
        }
    
        public void setFirstName(String firstName) {
            this.firstName = firstName;
        }
    
        public String getLastName() {
            return lastName;
        }
    
        public void setLastName(String lastName) {
            this.lastName = lastName;
        }
    
        public String getEmail() {
            return email;
        }
    
        public void setEmail(String email) {
            this.email = email;
        }
    }

ErrorResponse.java

package com.example.demo.object;
    
    import javax.xml.bind.annotation.XmlRootElement;
    import java.util.List;
    
    @XmlRootElement(name = "error")
    public class ErrorResponse {
    
        private String message;
        private List<String> details;
    
        public ErrorResponse(String message, List<String> details) {
    
            this.message = message;
            this.details = details;
        }
    
    
        public String getMessage() {
            return message;
        }
    
        public void setMessage(String message) {
            this.message = message;
        }
    
        public List<String> getDetails() {
            return details;
        }
    
        public void setDetails(List<String> details) {
            this.details = details;
        }
    }

EmployeeDB.java

package com.example.demo.repository;
    
    import com.example.demo.object.EmployeeVO;
    
    import java.util.ArrayList;
    
    public class EmployeeDB {
    
        private static ArrayList<EmployeeVO> employeeVOArrayList = new ArrayList<>();
    
        public static void addEmployee(EmployeeVO employeeVO){
    
            employeeVOArrayList.add(employeeVO);
        }
    
    
        public static EmployeeVO getEmployeeById(Integer id){
    
            for(EmployeeVO item : employeeVOArrayList){
    
                if(item.getEmployeeId().equals(id)){
    
                    return item;
                }
            }
    
            return null;
        }
    }

DemoApplication.java

package com.example.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class DemoApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(DemoApplication.class, args);
        }
    
    }

测试：

1) HTTP GET /employees/1 \[VALID\]

HTTP Status : 200
     
    {
        "employeeId": 1,
        "firstName": "John",
        "lastName": "Wick",
        "email": "howtodoinjava@gmail.com",
    }

2) HTTP GET /employees/23 \[INVALID\]

HTTP Status : 404
     
    {
        "message": "Record Not Found",
        "details": [
            "Invalid employee id : 23"
        ]
    }

3) HTTP POST /employees \[INVALID\]

Request

{
        "lastName": "Bill",
        "email": "ibill@gmail.com"
    }

Response

HTTP Status : 400
     
    {
        "message": "Validation Failed",
        "details": [
            "first name must not be empty"
        ]
    }

4) HTTP POST /employees \[INVALID\]

Request

{
        "email": "ibill@gmail.com"
    }

Response

HTTP Status : 400
     
    {
        "message": "Validation Failed",
        "details": [
            "last name must not be empty",
            "first name must not be empty"
        ]
    }

5) HTTP POST /employees \[INVALID\]

Request

{
        "firstName":"Lokesh",
        "email": "ibill_gmail.com" //invalid email in request
    }

Response

HTTP Status : 400
     
    {
        "message": "Validation Failed",
        "details": [
            "last name must not be empty",
            "email should be a valid email"
        ]
    }

源码打包下载地址：

[https://github.com/fengfanchen/Java/tree/master/ErrorHandling][https_github.com_fengfanchen_Java_tree_master_ErrorHandling]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxNzg0NDI3NjE_size_16_color_FFFFFF_t_70]: /images/20221014/3e9141677e9946e38f8a44946206ae3f.png
[https_github.com_fengfanchen_Java_tree_master_ErrorHandling]: https://github.com/fengfanchen/Java/tree/master/ErrorHandling