完善短路验证时，不完美的错误信息提示

前面进行短路验证时，我们发现短路验证虽然成功了，但是还有不完善的地方，如：

其他配置和类与短路验证中的一致

如何解决这个问题呢？

经过分析，我们知道，若类型转换失败, 默认情况下还会执行后面的拦截器, 还会进行后面的验证. 可以通过修改 ConversionErrorInterceptor 源代码的方式，使当类型转换失败时, 不再执行后续的验证拦截器, 而直接返回 input 的 result ，具体如何操作呢？

1. 在src 下创建一个和ConversionErrorInterceptor 所在包同名的包 com.opensymphony.xwork2.interceptor

2. 在包 com.opensymphony.xwork2.interceptor下创建一个和 ConversionErrorInterceptor 拦截器同名的类

3. 把原ConversionErrorInterceptor 拦截器中的代码复制到新创建的 ConversionErrorInterceptor 拦截器中

4. 修改新创建的 ConversionErrorInterceptor 拦截器中的代码，使其如果类型转换出错的情况下，就不在执行其后的拦截器链

其他配置和类与短路验证中的一致

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项目结构

/*
 * Copyright 2002-2007,2009 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.opensymphony.xwork2.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.conversion.impl.XWorkConverter;
import com.opensymphony.xwork2.util.ValueStack;
import org.apache.commons.lang3.StringEscapeUtils;

import java.util.HashMap;
import java.util.Map;

/**
 * <!-- START SNIPPET: description -->
 * ConversionErrorInterceptor adds conversion errors from the ActionContext to the Action's field errors.
 *
 * <p/>
 * This interceptor adds any error found in the {@link ActionContext}'s conversionErrors map as a field error (provided
 * that the action implements {@link ValidationAware}). In addition, any field that contains a validation error has its
 * original value saved such that any subsequent requests for that value return the original value rather than the value
 * in the action. This is important because if the value "abc" is submitted and can't be converted to an int, we want to
 * display the original string ("abc") again rather than the int value (likely 0, which would make very little sense to
 * the user).
 *
 *
 * <!-- END SNIPPET: description -->
 *
 * <p/> <u>Interceptor parameters:</u>
 *
 * <!-- START SNIPPET: parameters -->
 *
 * <ul>
 *
 * <li>None</li>
 *
 * </ul>
 *
 * <!-- END SNIPPET: parameters -->
 *
 * <p/> <u>Extending the interceptor:</u>
 *
 * <p/>
 *
 * <!-- START SNIPPET: extending -->
 *
 * Because this interceptor is not web-specific, it abstracts the logic for whether an error should be added. This
 * allows for web-specific interceptors to use more complex logic in the {@link #shouldAddError} method for when a value
 * has a conversion error but is null or empty or otherwise indicates that the value was never actually entered by the
 * user.
 *
 * <!-- END SNIPPET: extending -->
 *
 * <p/> <u>Example code:</u>
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 * <action name="someAction" class="com.examples.SomeAction">
 *     <interceptor-ref name="params"/>
 *     <interceptor-ref name="conversionError"/>
 *     <result name="success">good_result.ftl</result>
 * </action>
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * @author Jason Carreira
 */
public class ConversionErrorInterceptor extends AbstractInterceptor {

    /**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	public static final String ORIGINAL_PROPERTY_OVERRIDE = "original.property.override";

    protected Object getOverrideExpr(ActionInvocation invocation, Object value) {
        return escape(value);
    }

    protected String escape(Object value) {
        return "\"" + StringEscapeUtils.escapeJava(String.valueOf(value)) + "\"";
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {

        ActionContext invocationContext = invocation.getInvocationContext();
        Map<String, Object> conversionErrors = invocationContext.getConversionErrors();
        ValueStack stack = invocationContext.getValueStack();

        HashMap<Object, Object> fakie = null;

        for (Map.Entry<String, Object> entry : conversionErrors.entrySet()) {
            String propertyName = entry.getKey();
            Object value = entry.getValue();

            if (shouldAddError(propertyName, value)) {
                String message = XWorkConverter.getConversionErrorMessage(propertyName, stack);

                Object action = invocation.getAction();
                if (action instanceof ValidationAware) {
                    ValidationAware va = (ValidationAware) action;
                    va.addFieldError(propertyName, message);
                }

                if (fakie == null) {
                    fakie = new HashMap<Object, Object>();
                }

                fakie.put(propertyName, getOverrideExpr(invocation, value));
            }
        }

        if (fakie != null) {
            // if there were some errors, put the original (fake) values in place right before the result
            stack.getContext().put(ORIGINAL_PROPERTY_OVERRIDE, fakie);
            invocation.addPreResultListener(new PreResultListener() {
                public void beforeResult(ActionInvocation invocation, String resultCode) {
                    Map<Object, Object> fakie = (Map<Object, Object>) invocation.getInvocationContext().get(ORIGINAL_PROPERTY_OVERRIDE);

                    if (fakie != null) {
                        invocation.getStack().setExprOverrides(fakie);
                    }
                }
            });
        }
        
        Object action = invocation.getAction();
        if (action instanceof ValidationAware) {
            ValidationAware va = (ValidationAware) action;
           
            //如果 字段类型转换有错误 或者 action请求 有错误  直接返回不在调用下面的 invocation.invoke()，
            //这样就阻止了拦截器链的运行，使程序更有效率
            if(va.hasFieldErrors() || va.hasActionErrors()){
            	return "input";
            }
        }
        return invocation.invoke();
    }

    protected boolean shouldAddError(String propertyName, Object value) {
        return true;
    }
}

修改后的效果：