【注】本文译自：https://www.tutorialspoint.com/spring_boot/spring_boot_exception_handling.htm
对于企业应用而言，在 API 中解决好异样和谬误是至关重要的。本文将带你学习如果在 Spring Boot 中解决异样。
在学习异样解决前让咱们先来了解上面的注解：
Controller Advice
@ControllerAdvice 注解用于解决全局异样。
Exception Handler
@ExceptionHandler 注解是用于解决指定的异样并向客户端发送一个自定义的响应。
能够应用上面的代码来创立 @ControllerAdvice 类以解决全局异样：
package com.tutorialspoint.demo.exception;
import org.springframework.web.bind.annotation.ControllerAdvice;
@ControllerAdvice
public class ProductExceptionController {
}
定义一个继承 RuntimeException 的类。
package com.tutorialspoint.demo.exception;
public class ProductNotfoundException extends RuntimeException {
private static final long serialVersionUID = 1L;
}
如下所示，能够定义 @ExceptionHandler 办法来解决异样。这个办法该当被用于编写 Controller Advice 类文件。
@ExceptionHandler(value = ProductNotfoundException.class)
public ResponseEntity<Object> exception(ProductNotfoundException exception) {
}
当初，应用以下代码来抛出来自 API 的异样：
@RequestMapping(value = “/products/{id}”, method = RequestMethod.PUT)
public ResponseEntity<Object> updateProduct() {
throw new ProductNotfoundException();
}
残缺的异样解决代码如下所示。在这个例子中，咱们应用 PUT API 来更新产品。当更新产品时，如果找不到产品，返回的响应音讯是“Product not found”。留神 ProductNotFoundException 异样类该当继承 RuntimeException。
package com.tutorialspoint.demo.exception;
public class ProductNotfoundException extends RuntimeException {
private static final long serialVersionUID = 1L;
}
Controller Advice 类解决全局异样，如下所示。咱们能够在这个类文件中定义任何 Exception Handler 办法。
package com.tutorialspoint.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);
}
}
上面的 Product Service API controller 文件更新产品。如果产品不存在，就抛出 ProductNotFoundException 类。
package com.tutorialspoint.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.tutorialspoint.demo.exception.ProductNotfoundException;
import com.tutorialspoint.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);
}
}
主 Spring Boot 利用类文件如下：
package com.tutorialspoint.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);
}
}
产品 POJO 类 如下：
package com.tutorialspoint.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;
}
}
Maven build – pom.xml 代码如下所示：
<?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.tutorialspoint</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>
Gradle Build – build.gradle 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.tutorialspoint’
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’)
}
你能够应用 Maven 或 Gradle 命令构建 JAR 并运行 Spring Boot 利用：
Maven 命令如下：
mvn clean install
“BUILD SUCCESS”之后，你能够在 target 目录下找到 JAR 文件。
Gradle 能够应用如下命令：
gradle clean build
“BUILD SUCCESSFUL”后，你能够在 build/libs 目录下找到 JAR 文件。
你能够应用上面的命令运行 JAR 文件。
java –jar <JARFILE>
在 Tomcat 8080 端口启动利用，如下所示：
当初，在 POSTMAN 利用中单击上面的 URL，你能够看到如下输入：
更新 URL: http://localhost:8080/products/3