封装自定义异常

• 才开通博客没几天，不知道写什么东西，就把最近在项目中做的东西分享一下，开通博客也可以监督一下自己，技术的路很遥远，希望能通过写博客来让自己走的更远。

• 一般在web项目中都需要定义一个全局异常来处理一些业务方面的异常，下面是自定义异常的一些代码。

1.自定义一个异常，然后继承runtimeexception

/**
 * @author zhuwenwen
 * @date 2018/8/16 20:18
 */
@getter
public class customexception extends runtimeexception {
    /**
     * 异常编码
     */
    private integer code;

    /**
     * 附加数据
     */
    private object data;

    public customexception(string errormsg) {

        super(errormsg);
        this.code= customenum.error.getcode();
    }

    public customexception(string errormsg, integer code) {
        super(errormsg);
        this.code = code;
    }

    public customexception(integer code, string errormsg, throwable errorcourse) {
        super(errormsg,errorcourse);
        this.code = code;
    }

    public customexception(string message, integer code, object data) {
        super(message);
        this.code = code;
        this.data = data;
    }

}

2.定义一个全局异常处理的类

/**
 * 处理全局异常
 *
 * @author zhuwenwen
 * @date 2018/8/17 9:31
 */
@restcontrolleradvice
public class customexceptionhandler extends responseentityexceptionhandler implements customexceptionhanlertrit {


    private logger logger=loggerfactory.getlogger(customexceptionhandler.class);
    /**
     *
     * @see responseentityexceptionhandler#handleexceptioninternal
     */
    @override
    protected responseentity<object> handleexceptioninternal(exception ex, object body, httpheaders headers, httpstatus status,webrequest webrequest) {
        logger.warn("{}", ex.getmessage());

        return handleexception(customenum.failure_http.getcode() + status.value(), ex.getmessage(), null);
    }

    /**
     * 处理servletexception
     *
     * @param ex      异常
     * @return        异常处理结果
     */
    @exceptionhandler(value = {servletexception.class})
    protected final responseentity<object> handleservletexception(servletexception ex) {
        logger.error("{}", ex);

        return handleexception(customenum.failure_servlet.getcode(), ex.getmessage(), null);
    }

    /**
     * 处理sqlexception
     *
     * @param ex      异常
     * @return        异常处理结果
     */
    @exceptionhandler(value = {sqlexception.class})
    protected final responseentity<object> handlesqlexception(sqlexception ex) {
        logger.error("{}", ex);

        return handleexception(customenum.failure_db.getcode(), ex.getmessage(), null);
    }

    /**
     * 处理constraintviolationexception
     *
     * @param ex      异常
     * @return        异常处理结果
     */
    @exceptionhandler(value = {constraintviolationexception.class})
    protected final responseentity<object> handleconstraintviolationexception(constraintviolationexception ex) {
        logger.error("{}", ex);

        string message = ex.getmessage();
        if (ex.getconstraintviolations() != null && !ex.getconstraintviolations().isempty()) {
            message = ex.getconstraintviolations().stream().findfirst().ispresent()
                    ? ex.getconstraintviolations().stream().findfirst().get().getmessage() : null;
        }

        return handleexception(customenum.failure_validation.getcode(), message, null);
    }

    /**
     * 处理morphedexception
     *
     * @param ex      异常
     * @return        异常处理结果
     */
    @exceptionhandler(value = {customexception.class})
    protected final responseentity<object> handlemorphedexception(customexception ex) {
        logger.info("{}", ex);

        return handleexception(ex.getcode(), ex.getmessage(),ex.getdata());
    }

    /**
     * 处理runtimeexception
     *
     * @param ex      异常
     * @return        异常处理结果
     */
    @exceptionhandler(value = {runtimeexception.class})
    protected final responseentity<object> handleruntimeexception(runtimeexception ex) {
        logger.error("{}", ex);

        return handleexception(customenum.failure_unknown.getcode(), ex.getmessage(), null);
    }

}

3.封装成一个组件，可以打成jar包，供多个项目使用,那么可以自定义一个注解，然后在启动类上加上这个注解，即可使用。下面是一个简单的demo

/**
 * @author zhuwenwen
 * @date 2018/8/17 11:02
 */

@target(elementtype.type)
@retention(retentionpolicy.runtime)
@import(customexceptionhandler.class)
@documented
public @interface enablecustomexception {
    /**
     * 是否开启
     * @return
     */
    boolean enabled() default true;


}

/**
 * @author zhuwenwen
 * @date 2018/8/17 14:47
 */
public class customimportbeandefination implements importbeandefinitionregistrar {
    @override
    public void registerbeandefinitions(annotationmetadata annotationmetadata, beandefinitionregistry beandefinitionregistry) {
        //是否含有@enablecustomexception注解
        if (annotationmetadata.isannotated(enablecustomexception.class.getname())){
            //获取该注解上面的所有属性，然后封装成一个map
            multivaluemap<string, object> attributes = annotationmetadata.getallannotationattributes(enablecustomexception.class.getname());
            if(attributes.get(enablecustomexceptioncode.enabled).equals(boolean.true)){
                beandefinitionbuilder beandefinitionbuilder = beandefinitionbuilder.rootbeandefinition(customexceptionhandler.class);
                beandefinitionregistry.registerbeandefinition(customexceptionhandler.class.getname(),beandefinitionbuilder.getbeandefinition());
            }
        }
    }
}