Springboot 同意异常处理和信息返回

统一异常处理与信息返回

pom.xml文件

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
    </properties>

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

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

application.properties配置文件

# 应用名称
spring.application.name=demo

创建启动类

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

创建统一信息返回类

public class Resp<T> {

    //服务端返回的错误码
    private int code = 200;
    //服务端返回的错误信息
    private String msg = "success";
    //我们服务端返回的数据
    private T data;

    private Resp(int code,String msg,T data){
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public static <T> Resp success(T data){
        Resp resp = new Resp(200, "success", data);
        return resp;
    }

    public static <T> Resp success(String msg,T data){
        Resp resp = new Resp(200,msg, data);
        return resp;
    }

    public static <T> Resp error(AppExceptionCodeMsg appExceptionCodeMsg){
        Resp resp = new Resp(appExceptionCodeMsg.getCode(), appExceptionCodeMsg.getMsg(), null);
        return resp;
    }
    public static <T> Resp error(int code,String msg){
        Resp resp = new Resp(code,msg, null);
        return resp;
    }

    public int getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }

    public T getData() {
        return data;
    }

}

创建全局统一异常处理类

@ControllerAdvice
public class GlobalExceptionHandler {


    @ExceptionHandler(value = {Exception.class})
    @ResponseBody
    public <T> Resp<T> exceptionHandler(Exception e){
        //这里先判断拦截到的Exception是不是我们自定义的异常类型
        if(e instanceof AppException){
            AppException appException = (AppException)e;
            return Resp.error(appException.getCode(),appException.getMsg());
        }

        //如果拦截的异常不是我们自定义的异常(例如：数据库主键冲突)
        return Resp.error(500,"服务器端异常");
    }
}

创建一个枚举类型

//这个枚举类中定义的都是跟业务有关的异常
public enum AppExceptionCodeMsg {

    INVALID_CODE(10000,"验证码无效"),
    USERNAME_NOT_EXISTS(10001,"用户名不存在"),
    USER_CREDIT_NOT_ENOUTH(10002,"用户积分不足");
    ;

    private int code ;
    private String msg ;

    public int getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }


    AppExceptionCodeMsg(int code, String msg){
        this.code = code;
        this.msg = msg;
    }

}

创建自定义的异常类

public class AppException extends RuntimeException{

    private int code = 500;
    private String msg = "服务器异常";


    public AppException(AppExceptionCodeMsg appExceptionCodeMsg){
        super();
        this.code = appExceptionCodeMsg.getCode();
        this.msg = appExceptionCodeMsg.getMsg();

    }

    public AppException(int code,String msg){
        super();
        this.code = code;
        this.msg = msg;

    }

    public int getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }

}

创建一个controller

@RestController
public class DemoController {


    @GetMapping("demo")
    public Resp<String> demo1(String name){

        if("ok".equals(name)){
            return Resp.success("succ");
        }
        if("err".equals(name)){
            //抛业务相关的异常
            throw new AppException(AppExceptionCodeMsg.USERNAME_NOT_EXISTS);
        }

        if("errcode".equals(name)){
            throw new AppException(AppExceptionCodeMsg.INVALID_CODE);
        }
        if("0".equals(name)){
            int i=1/0;
        }

        //检查用户积分是否足够，如果不够，就抛出异常
        if("notenough".equals(name)){
            throw new AppException(AppExceptionCodeMsg.USER_CREDIT_NOT_ENOUTH);
        }

        return Resp.success("default");
    }
    
   @GetMapping("list")
    public Resp<List> list(){
		List<String> list = Arrays.asList("zhangsan","lisi","wangwu");

        return Resp.success(list);
    }
}