处理多个验证注释错误消息

Question

我正在使用注释在 SpringMVC 中尝试验证...

我对一个字段使用了 2 个注释来验证

@NotEmpty(message="required")

@Size(min="3" max="8" message="超出范围")

私人字符串密码；

我面临的问题是，当该字段留空时，它会显示两个错误消息（*必需以及超出范围）。但我想显示其中一个错误消息，而不是两者都显示......

是否可以通过一条消息进行限制？如果是这样，这种情况的可能性是什么？

任何建议和指导表示赞赏..提前感谢...

Answer 1

有一个关于那个的问题。您可以查看以下链接：

In Spring MVC validation, Is it possible to show only one error message per field at a time?

Answer 2

我也遇到了同样的问题，所以我创建了只显示第一个错误的自定义错误标签 - 随意使用它：

a] 创建自定义标签类

package cz.devmint.springext.web.tags.form;

import javax.servlet.jsp.JspException;

import org.apache.commons.lang.StringUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.web.servlet.tags.form.ErrorsTag;
import org.springframework.web.servlet.tags.form.TagWriter;

public class ErrorsTagExt extends ErrorsTag {

private boolean firstErrorOnly = true;

public boolean isFirstErrorOnly() {
    return firstErrorOnly;
}

public void setFirstErrorOnly(boolean firstErrorOnly) {
    this.firstErrorOnly = firstErrorOnly;
}

@Override
protected void renderDefaultContent(TagWriter tagWriter) throws JspException {
    tagWriter.startTag(getElement());
    writeDefaultAttributes(tagWriter);
    String delimiter = ObjectUtils.getDisplayString(evaluate("delimiter", getDelimiter()));
    String[] errorMessages = getBindStatus().getErrorMessages();
    for(int i = 0; i < errorMessages.length; i++) {
        String errorMessage = errorMessages[i];
        if (i > 0) {
            tagWriter.appendValue(delimiter);
        }
        tagWriter.appendValue(getDisplayString(errorMessage));
        if (firstErrorOnly) break;
    }
    tagWriter.endTag();
}

b] 要使用自定义标签，您必须创建标签库描述符 - 您可以简单地从 spring 的标签库描述符中复制 ErrorsTag 声明（在 META-INF 目录中名为 @987654322 的 spring-webmvc-3.2.1.RELEASE.jar @) 并添加您自己的属性firstErrorOnly。下面是从我的库中提取的完整示例 - 请参阅代码中的 cmets 可以更改和自定义的内容：

<?xml version="1.0" encoding="UTF-8"?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    version="2.0">

<description>Custom extension to Spring Framework JSP Tag Library</description>
<tlib-version>3.0</tlib-version>
<short-name>tags</short-name>
<!-- use your own uri -->
<uri>http://cz.devmint.spring-ext/tags</uri>
<tag>
    <description>Renders field errors in an HTML 'span' tag.</description>
    <name>errors</name>
    <!-- use your own package - fully qualified name of your tag class  -->
    <tag-class>cz.devmint.springext.web.tags.form.ErrorsTagExt</tag-class>
    <body-content>JSP</body-content>
    <variable>
        <name-given>messages</name-given>
        <variable-class>java.util.List</variable-class>
    </variable>
    <!-- this attribute declaration is the only change when compare with spring's original tag definition -->   
    <attribute>
        <description>Whether to render the first error for given field only</description>
        <name>firstErrorOnly</name>
        <required>false</required>
        <rtexprvalue>false</rtexprvalue>
    </attribute>
    <attribute>
        <description>Path to errors object for data binding</description>
        <name>path</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Standard Attribute</description>
        <name>id</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>Enable/disable HTML escaping of rendered values.</description>
        <name>htmlEscape</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>Delimiter for displaying multiple error messages. Defaults to the br tag.</description>
        <name>delimiter</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>Equivalent to "class" - HTML Optional Attribute</description>
        <name>cssClass</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>Equivalent to "style" - HTML Optional Attribute</description>
        <name>cssStyle</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Standard Attribute</description>
        <name>lang</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Standard Attribute</description>
        <name>title</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Standard Attribute</description>
        <name>dir</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Standard Attribute</description>
        <name>tabindex</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onclick</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>ondblclick</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onmousedown</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onmouseup</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onmouseover</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onmousemove</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onmouseout</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onkeypress</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onkeyup</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>HTML Event Attribute</description>
        <name>onkeydown</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <description>Specifies the HTML element that is used to render the enclosing errors.</description>
        <name>element</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <dynamic-attributes>true</dynamic-attributes>
</tag>
</taglib>

将此xml文件放入WEB-INF/tld/spring-ext.tld

在jsp页面添加声明：

<%@taglib prefix="spring-ext" uri="http://cz.devmint.spring-ext/tags" %>    

使用自定义标签代替spring的ErrorsTag：

<spring-ext:errors path="dummy" firstErrorOnly="true" />