springboot系类代码：import org.springframework.boot.autoconfigure.web.ErrorProperties

将配置从代码中分离到XML或者properties中，这种spring配置外部化的方式成为外部配置。
spring 自动配置，spring-boot-autoconfigure依赖默认配置项，根据添加的依赖自动加载相关的配置属性并启动依赖。应用者只需要引入对应的start jar包，spring boot 就可以自动扫描和加载依赖信息。

package com.programb;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;


@SpringBootApplication
@RestController
public class ErrorControllerApplication {

    private void randomException() throws Exception {
        Exception[] exceptions = { //异常集合
                new NullPointerException(),
                new ArrayIndexOutOfBoundsException(),
                new NumberFormatException(),
                new SQLException()};
        //发生概率
        double probability = 0.75;
        if (Math.random() < probability) {
            //情况1：要么抛出异常
            throw exceptions[(int) (Math.random() * exceptions.length)];
        } else {
            //情况2：要么继续运行
        }

    }


    @GetMapping("/")
    public List index() throws Exception {
        randomException();
        return Arrays.asList("正常用户数据1!", "正常用户数据2! 请按F5刷新!!");
    }

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

package com.programb.error;

import org.springframework.boot.autoconfigure.web.ErrorProperties;
import org.springframework.boot.autoconfigure.web.ErrorProperties.IncludeStacktrace;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.autoconfigure.web.servlet.error.AbstractErrorController;
import org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController;
import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.util.WebUtils;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.time.LocalDateTime;


@Order(Ordered.HIGHEST_PRECEDENCE)
@Component
public class ErrorInfoBuilder implements HandlerExceptionResolver, Ordered {


    private final static String ERROR_NAME = "programb.error";


    private ErrorProperties errorProperties;

    public ErrorProperties getErrorProperties() {
        return errorProperties;
    }

    public void setErrorProperties(ErrorProperties errorProperties) {
        this.errorProperties = errorProperties;
    }


    public ErrorInfoBuilder(ServerProperties serverProperties) {
        this.errorProperties = serverProperties.getError();
    }


    public ErrorInfo getErrorInfo(HttpServletRequest request) {

        return getErrorInfo(request, getError(request));
    }


    public ErrorInfo getErrorInfo(HttpServletRequest request, Throwable error) {
        ErrorInfo errorInfo = new ErrorInfo();
        errorInfo.setTime(LocalDateTime.now().toString());
        errorInfo.setUrl((String) request.getAttribute(WebUtils.ERROR_REQUEST_URI_ATTRIBUTE));
        errorInfo.setError(error.toString());
        errorInfo.setStatusCode(getHttpStatus(request).value());
        errorInfo.setReasonPhrase(getHttpStatus(request).getReasonPhrase());
        errorInfo.setStackTrace(getStackTraceInfo(error, isIncludeStackTrace(request)));
        return errorInfo;
    }


    public Throwable getError(HttpServletRequest request) {
        //根据HandlerExceptionResolver接口方法来获取错误.
        Throwable error = (Throwable) request.getAttribute(ERROR_NAME);
        //根据Request对象获取错误.
        if (error == null) {
            error = (Throwable) request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE);
        }
        //当获取错误非空,取出RootCause.
        if (error != null) {
            while (error instanceof ServletException && error.getCause() != null) {
                error = error.getCause();
            }
        }//当获取错误为null,此时我们设置错误信息即可.
        else {
            String message = (String) request.getAttribute(WebUtils.ERROR_MESSAGE_ATTRIBUTE);
            if (StringUtils.isEmpty(message)) {
                HttpStatus status = getHttpStatus(request);
                message = "Unknown Exception With " + status.value() + " " + status.getReasonPhrase();
            }
            error = new Exception(message);
        }
        return error;
    }


    public HttpStatus getHttpStatus(HttpServletRequest request) {
        Integer statusCode = (Integer) request.getAttribute(WebUtils.ERROR_STATUS_CODE_ATTRIBUTE);
        try {
            return statusCode != null ? HttpStatus.valueOf(statusCode) : HttpStatus.INTERNAL_SERVER_ERROR;
        } catch (Exception ex) {
            return HttpStatus.INTERNAL_SERVER_ERROR;
        }
    }


    public String getStackTraceInfo(Throwable error, boolean flag) {
        if (!flag) {
            return "omitted";
        }
        StringWriter stackTrace = new StringWriter();
        error.printStackTrace(new PrintWriter(stackTrace));
        stackTrace.flush();
        return stackTrace.toString();
    }


    public boolean isIncludeStackTrace(HttpServletRequest request) {

        //读取错误配置(server.error.include-stacktrace=NEVER)
        IncludeStacktrace includeStacktrace = errorProperties.getIncludeStacktrace();

        //情况1：若IncludeStacktrace为ALWAYS
        if (includeStacktrace == IncludeStacktrace.ALWAYS) {
            return true;
        }
        //情况2：若请求参数含有trace
        if (includeStacktrace == IncludeStacktrace.ON_TRACE_PARAM) {
            String parameter = request.getParameter("trace");
            return parameter != null && !"false".equals(parameter.toLowerCase());
        }
        //情况3：其它情况
        return false;
    }


    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
        request.setAttribute(ERROR_NAME, ex);
        return null;
    }


    @Override
    public int getOrder() {
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

package com.programb.error;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;


@Controller
@RequestMapping("${server.error.path:/error}")
public class GlobalErrorController implements ErrorController {

    @Autowired
    private ErrorInfoBuilder errorInfoBuilder;

 
    private final static String DEFAULT_ERROR_VIEW = "error";


    @Override
    public String getErrorPath() {
        return errorInfoBuilder.getErrorProperties().getPath();
    }


    @RequestMapping(produces = MediaType.TEXT_HTML_VALUE)
    @ResponseBody
    public ModelAndView errorHtml(HttpServletRequest request) {
        return new ModelAndView(DEFAULT_ERROR_VIEW, "errorInfo", errorInfoBuilder.getErrorInfo(request));
    }


    @RequestMapping
    @ResponseBody
    public ErrorInfo error(HttpServletRequest request) {
        return errorInfoBuilder.getErrorInfo(request);
    }


}

<?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>
    <!--基本信息 -->
    <groupId>com.programb</groupId>
    <artifactId>springboot-error-controller</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>spring-boot-error-controller</name>
    <description>springboot异常</description>

    <!--继承信息 -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.M4</version>
        <relativePath/>
    </parent>

    <!--依赖管理 -->
    <dependencies>
        <dependency> <!--添加Web依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency> <!--添加Thymeleaf依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency><!--添加Test依赖 -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <!--指定远程仓库（含插件）-->
    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.spring.io/snapshot</url>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <url>http://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>

    <!--构建插件 -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>