用@RequestBody，@ResponseBody，解决JSon自动绑定。
接着就发现，如果遇到RuntimeException，需要给出一个默认返回JSON。
当这个Controller中任何一个方法发生异常，一定会被这个方法拦截到。然后，输出日志。绑定JSon中并返回。
接下来写一个测试的controller:

package com.springboot.exception.controller;
 
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @Author 18011618
* @Date 15:59 2018/7/13
* @Function 测试异常的controller
*/
@RestController
public class ExceptionController {
 
    @RequestMapping("/exce")
    public String showInfo(){
        System.err.println("dddddddddddddd");
        String info ="你好";
        int a = 1/0;
        return info;
    }
}

结构

Pom.xml

看一下对应的Pom.xml文件内容:

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.learn</groupId>
    <artifactId>error</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>error</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <!--  -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.18</version>
        </dependency>
        <!--  -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.44</version>
        </dependency>

        <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>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

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

</project>

定义一个封装json的工具类,使用阿里巴巴的fastjson：

package com.springboot.exception.json;
 
import com.alibaba.fastjson.JSON;
import lombok.Data;
 
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
 
/**
 * lombok格式化数据
 */
@Data
public class JsonResult implements Serializable{
 
    private int code;   //返回码 非0即失败
    private String msg; //消息提示
    private Map<String, Object> data; //返回的数据
 
    public JsonResult(){};
 
    public JsonResult(int code, String msg, Map<String, Object> data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }
 
    public static String success() {
        return success(new HashMap(0));
    }
    public static String success(Map<String, Object> data) {
        return JSON.toJSONString(new JsonResult(0, "解析成功", data));
    }
 
    public static String failed() {
        return failed("解析失败");
    }
    public static String failed(String msg) {
        return failed(-1, msg);
    }
    public static String failed(int code, String msg) {
        return JSON.toJSONString(new JsonResult(code, msg, new HashMap(0)));
    }
 
}

接下来定义一个全局异常处理类:

package com.learn.error.exception;


import com.learn.error.json.JsonResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.ConversionNotSupportedException;
import org.springframework.beans.TypeMismatchException;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.IOException;

@ControllerAdvice
@ResponseBody
public class GlobalExceptionHandler {

    private static final String logExceptionFormat = "Capture Exception By GlobalExceptionHandler: Code: %s Detail: %s";
    private static       Logger log                = LoggerFactory.getLogger(GlobalExceptionHandler.class);

    //运行时异常
    @ExceptionHandler(RuntimeException.class)
    public String runtimeExceptionHandler(RuntimeException ex) {
        return resultFormat(1, ex);
    }

    //空指针异常
    @ExceptionHandler(NullPointerException.class)
    public String nullPointerExceptionHandler(NullPointerException ex) {
        System.err.println("NullPointerException:");
        return resultFormat(2, ex);
    }

    //类型转换异常
    @ExceptionHandler(ClassCastException.class)
    public String classCastExceptionHandler(ClassCastException ex) {
        return resultFormat(3, ex);
    }

    //IO异常
    @ExceptionHandler(IOException.class)
    public String iOExceptionHandler(IOException ex) {
        return resultFormat(4, ex);
    }

    //未知方法异常
    @ExceptionHandler(NoSuchMethodException.class)
    public String noSuchMethodExceptionHandler(NoSuchMethodException ex) {
        return resultFormat(5, ex);
    }

    //数组越界异常
    @ExceptionHandler(IndexOutOfBoundsException.class)
    public String indexOutOfBoundsExceptionHandler(IndexOutOfBoundsException ex) {
        return resultFormat(6, ex);
    }

    //400错误
    @ExceptionHandler({HttpMessageNotReadableException.class})
    public String requestNotReadable(HttpMessageNotReadableException ex) {
        System.out.println("400..requestNotReadable");
        return resultFormat(7, ex);
    }

    //400错误
    @ExceptionHandler({TypeMismatchException.class})
    public String requestTypeMismatch(TypeMismatchException ex) {
        System.out.println("400..TypeMismatchException");
        return resultFormat(8, ex);
    }

    //400错误
    @ExceptionHandler({MissingServletRequestParameterException.class})
    public String requestMissingServletRequest(MissingServletRequestParameterException ex) {
        System.out.println("400..MissingServletRequest");
        return resultFormat(9, ex);
    }

    //405错误
    @ExceptionHandler({HttpRequestMethodNotSupportedException.class})
    public String request405(HttpRequestMethodNotSupportedException ex) {
        return resultFormat(10, ex);
    }

    //406错误
    @ExceptionHandler({HttpMediaTypeNotAcceptableException.class})
    public String request406(HttpMediaTypeNotAcceptableException ex) {
        System.out.println("406...");
        return resultFormat(11, ex);
    }

    //500错误
    @ExceptionHandler({ConversionNotSupportedException.class, HttpMessageNotWritableException.class})
    public String server500(RuntimeException ex) {
        System.out.println("500...");
        return resultFormat(12, ex);
    }

    //栈溢出
    @ExceptionHandler({StackOverflowError.class})
    public String requestStackOverflow(StackOverflowError ex) {
        return resultFormat(13, ex);
    }

    //除数不能为0
    @ExceptionHandler({ArithmeticException.class})
    public String arithmeticException(ArithmeticException ex) {
        return resultFormat(13, ex);
    }


    //其他错误
    @ExceptionHandler({Exception.class})
    public String exception(Exception ex) {
        return resultFormat(14, ex);
    }

    private <T extends Throwable> String resultFormat(Integer code, T ex) {
        ex.printStackTrace();
        log.error(String.format(logExceptionFormat, code, ex.getMessage()));
        return JsonResult.failed(code, ex.getMessage());
    }
}

注解:

@ControllerAdvice: 可以用于定义@ExceptionHandler、@InitBinder、@ModelAttribute，并应用到所有@RequestMapping中
@ExceptionHandler:标识异常类型对应的处理方法
比如下面这个方法:就是处理当遇到了空指针异常对应的处理方法

@ExceptionHandler(NullPointerException.class)
public String nullPointerExceptionHandler(NullPointerException ex) {
    System.err.println("NullPointerException:");
    return resultFormat(2, ex);
}

最看看一下对应的application.yaml配置文件

server:
  port: 8888

最后写一个启动应用类:

package com.springboot.exception;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
/**
 * @Author 18011618
 * @Description
 * @Date 16:00 2018/7/13
 * @Modify By
 */
@SpringBootApplication
public class ExceptionApplication {
    public static void main(String[] args) {
        SpringApplication.run(ExceptionApplication.class,args);
    }
}

这个时候启动应用类之后，然后访问浏览器 http://localhost:8888/exce 对应的效果如下

如果不想用@ResponseBody的话，可以使用@RestControllerAdvice代替@ControllerAdvice

OK 效果实现了,它主要是在Spring mvc 启动时调用RequestMappingHandlerAdapter类的initControllerAdviceCache()方法进行初始化