SpringBoot 异常处理

下面的示例中对请求进行验证，并添加自定义的错误信息处理。

1. 创建 rest api 和模型类

EmployeeRESTController.java

import javax.validation.Valid;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmployeeRESTController {
    @PostMapping(value = "/employees")
    public ResponseEntity<EmployeeVO> addEmployee (@Valid @RequestBody EmployeeVO employee)
    {
        return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);
    }
     
    @GetMapping(value = "/employees/{id}")
    public ResponseEntity<EmployeeVO> getEmployeeById (@PathVariable("id") int id)
    {
        EmployeeVO employee = null;
         
        if(employee == null) {
             throw new RecordNotFoundException("Invalid employee id : " + id);
        }
        return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);
    }
}

EmployeeVO.java

import java.io.Serializable;

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;

@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeVO implements Serializable
{
    private Integer employeeId;
    private String firstName;
    private String lastName;
    private String email;
 
    public EmployeeVO(Integer id, String firstName, String lastName, String email) {
        super();
        this.employeeId = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }
 
    public EmployeeVO() {
    }
     
    //Removed setter/getter for readability
}

2. Spring boot 异常处理 - rest 请求验证

2.1 spring 默认验证支持

修改模型类，添加验证。

EmployeeVO.java

package com.example.demoasync.valid;

import java.io.Serializable;

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;

@XmlRootElement(name = "employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class EmployeeVO implements Serializable
{
    private static final long serialVersionUID = 1L;
     
    public EmployeeVO(Integer id, String firstName, String lastName, String email) {
        super();
        this.employeeId = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }
 
    public EmployeeVO() {
    }
 
    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;
     
    //Removed setter/getter for readability
    
}

通过 @Valid 注解开启验证：

@PostMapping(value = "/employees")
public ResponseEntity<EmployeeVO> addEmployee (@Valid @RequestBody EmployeeVO employee)
{
    EmployeeDB.addEmployee(employee);
    return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);
}

2.2 异常模型类

RecordNotFoundException.java

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);
    }
}

ErrorResponse.java

import java.util.List;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement(name = "error")
public class ErrorResponse
{
    public ErrorResponse(String message, List<String> details) {
        super();
        this.message = message;
        this.details = details;
    }
 
    //General error message about nature of error
    private String message;
 
    //Specific errors in API request processing
    private List<String> details;
 
    //Getter and setters
}

2.3 自定义 ExceptionHandler

CustomExceptionHandler.java

import java.util.ArrayList;
import java.util.List;
 
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;
 
@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> details = new ArrayList<>();
        details.add(ex.getLocalizedMessage());
        ErrorResponse error = new ErrorResponse("Record Not Found", details);
        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);
    }
}

3. 测试

1）HTTP GET /employees/23

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

2）HTTP POST /employees

请求：

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

响应：

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

3）HTTP POST /employees

请求：

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

响应：

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