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responseentity 返回异常_Spring Boot异常处理

news 来源：原创 2024/9/19 8:58:42

处理API中的异常和错误并向客户端发送适当的响应对企业应用程序有利。在本章中，将学习如何在Spring Boot中处理异常。

在继续进行异常处理之前，了解以下注解。

控制器Advice

@ControllerAdvice是一个注解，用于全局处理异常。

异常处理程序

@ExceptionHandler是一个注释，用于处理特定异常并将自定义响应发送到客户端。使用以下代码创建@ControllerAdvice类来全局处理异常 -

package com.yiibai.demo.exception;

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

@ControllerAdvice
   public class ProductExceptionController {
}
Java

定义一个扩展RuntimeException类的子类。

package com.yiibai.demo.exception;

public class ProductNotfoundException extends RuntimeException {
   private static final long serialVersionUID = 1L;
}
Java

可以定义@ExceptionHandler方法来处理异常，如图所示。此方法应用于编写Controller Advice类文件。

@ExceptionHandler(value = ProductNotfoundException.class)

public ResponseEntity<Object> exception(ProductNotfoundException exception) {
}
Java

现在，使用下面给出的代码从API中抛出异常。

@RequestMapping(value = "/products/{id}", method = RequestMethod.PUT)
public ResponseEntity<Object> updateProduct() { 
   throw new ProductNotfoundException();
}
Java

下面给出了处理异常的完整代码。在此示例中，使用PUT API更新产品。此处，在更新产品时，如果找不到产品，则将响应错误消息返回为:"ProductNotFoundException"。请注意，ProductNotFoundException异常类应该扩展RuntimeException。

package com.yiibai.demo.exception;
public class ProductNotfoundException extends RuntimeException {
   private static final long serialVersionUID = 1L;
}
Java

下面给出了用于全局处理异常的ControllerAdvice类。在这个类文件中定义任何异常处理方法。

package com.yiibai.demo.exception;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

@ControllerAdvice
public class ProductExceptionController {
   @ExceptionHandler(value = ProductNotfoundException.class)
   public ResponseEntity<Object> exception(ProductNotfoundException exception) {
      return new ResponseEntity<>("Product not found", HttpStatus.NOT_FOUND);
   }
}
Java

下面给出了Product Service API控制器文件以更新产品。如果找不到产品，则抛出ProductNotFoundException类。

package com.yiibai.demo.controller;

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

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.yiibai.demo.exception.ProductNotfoundException;
import com.yiibai.demo.model.Product;

@RestController
public class ProductServiceController {
   private static Map<String, Product> productRepo = new HashMap<>();
   static {
      Product honey = new Product();
      honey.setId("1");
      honey.setName("Honey");
      productRepo.put(honey.getId(), honey);

      Product almond = new Product();
      almond.setId("2");
      almond.setName("Almond");
      productRepo.put(almond.getId(), almond);
   }

   @RequestMapping(value = "/products/{id}", method = RequestMethod.PUT)
   public ResponseEntity<Object> updateProduct(@PathVariable("id") String id, @RequestBody Product product) { 
      if(!productRepo.containsKey(id))throw new ProductNotfoundException();
      productRepo.remove(id);
      product.setId(id);
      productRepo.put(id, product);
      return new ResponseEntity<>("Product is updated successfully", HttpStatus.OK);
   }
}
Java

Spring Boot应用程序主类文件的代码如下 -

package com.yiibai.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);
   }
}
Java

产品POJO类的代码如下 -

package com.yiibai.demo.model;
public class Product {
   private String id;
   private String name;

   public String getId() {
      return id;
   }
   public void setId(String id) {
      this.id = id;
   }
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }
}
Java

Maven build的代码 - 文件:pom.xml 如下所示 -

<?xml version = "1.0" encoding = "UTF-8"?>
<project xmlns = "http://maven.apache.org/POM/4.0.0" 
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://maven.apache.org/POM/4.0.0 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">

   <modelVersion>4.0.0</modelVersion>
   <groupId>com.yiibai</groupId>
   <artifactId>demo</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>demo</name>
   <description>Demo project for Spring Boot</description>

   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>1.5.8.RELEASE</version>
      <relativePath/> 
   </parent>

   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
      <java.version>1.8</java.version>
   </properties>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>

</project>
XML

Gradle构建文件:build.gradle 的代码如下 -

buildscript {
   ext {
      springBootVersion = '1.5.8.RELEASE'
   }
   repositories {
      mavenCentral()
   }
   dependencies {
      classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
   }
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

group = 'com.yiibai'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
   mavenCentral()
}
dependencies {
   compile('org.springframework.boot:spring-boot-starter-web')
   testCompile('org.springframework.boot:spring-boot-starter-test')
}
Java

创建可执行的JAR文件，并使用Maven或Gradle命令运行Spring Boot应用程序，对于Maven，可以使用以下命令 -