jsp自定义标签 <dict:select... 选择标签和数据字典

jsp自定义标签，用于项目便捷开发。在实际项目开发中，我们大多数时候会采用数据字典来储存项目中一些数据，比如性别、国际、类型等，用数据字典存储很方便，因此在数据库中添加一张数据字典表t_dict_value，有做过的项目中采用两张表进行数据字典的管理，个人在设计数据字典的时候感觉一张表也够用了。

1.看建表语句：

CREATE TABLE `t_dict_value` (
	  `id` varchar(36) NOT NULL,
	  `dict_name` varchar(36) default NULL,
	  `item_code` varchar(36) default NULL,
	  `item_desc` varchar(36) default NULL,
	  PRIMARY KEY  (`id`),
	  UNIQUE KEY `item_code` (`item_code`)
	) ENGINE=MyISAM DEFAULT CHARSET=utf-8;

2.我的自定义标签是基于数据字典表使用的，当然后续业务中有需要也可以***特定的自定义标签，接下来开始自定义标签，首先写一个DictSelectTag类，代码如下：

package com.infopatent.juangetljc.web.controller.core;

import java.io.IOException;
import java.util.List;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.commons.lang3.StringUtils;

import com.infopatent.juangetljc.core.DictValue;

public class DictSelectTag extends TagSupport  {

    private String dictName;
    private boolean defaultValue;
    private String value;
    private String name;
    private String id;
    private String cssClass;
    private String styleClass;
    private String multiple;
    private String onChange;

    public String getCssClass() {
        return cssClass;
    }

    public void setCssClass(String cssClass) {
        this.cssClass = cssClass;
    }

    public String getStyleClass() {
        return styleClass;
    }

    public void setStyleClass(String styleClass) {
        this.styleClass = styleClass;
    }

    public String getMultiple() {
        return multiple;
    }

    public void setMultiple(String multiple) {
        this.multiple = multiple;
    }

    public String getOnChange() {
        return onChange;
    }

    public void setOnChange(String onChange) {
        this.onChange = onChange;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getDictName() {
        return dictName;
    }

    public void setDictName(String dictName) {
        this.dictName = dictName;
    }
    
    public boolean isDefaultValue() {
        return defaultValue;
    }

    public void setDefaultValue(boolean defaultValue) {
        this.defaultValue = defaultValue;
    }
    
    
    @Override
    public int doEndTag() throws JspException{
        DictValue dict = new DictValue();
        List<DictValue> dict_list = dict.getRepository().findByProperty(DictValue.class,"dictName",dictName);
        JspWriter out = pageContext.getOut();
        StringBuffer sb = new StringBuffer();
        sb.append("<select name='"+this.getName()+"' id='"+this.getId()+"'");
        if(!StringUtils.isEmpty(this.getCssClass())){
            sb.append("class=\"" + this.getCssClass() + "\" ");
        }
        if(!StringUtils.isEmpty(this.getStyleClass())){
            sb.append("style=\"" + this.getStyleClass() + "\" ");
        }
        if(!StringUtils.isEmpty(this.getMultiple())){
            sb.append("multiple=\"" + this.getMultiple() + "\" ");
        }
        if(!StringUtils.isEmpty(this.getOnChange())){
            sb.append("onchange=\"" + this.getOnChange() + "\" ");
        }
        sb.append(">");
        if(this.isDefaultValue()){  
            sb.append("<option value=''>--请选择--</option>");  
        }
        for(DictValue dc:dict_list){
            if(dc.getItemCode().equals(this.getValue())){
                sb.append("<option value='"+dc.getItemCode()+"' selected='selected'>");
            }else{
                sb.append("<option value='"+dc.getItemCode()+"'>");
            }
            sb.append(dc.getItemDesc()+"</option>");
        }
        sb.append("</select>");
        try {
            out.write(sb.toString());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            throw new JspException(e);
        }
        return TagSupport.EVAL_PAGE;
    }
    
}

3.再写一个DictLabelTag类用于显示字典中的值，代码如下：

package com.infopatent.juangetljc.web.controller.core;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import org.springframework.web.servlet.tags.form.OptionsTag;

import com.infopatent.juangetljc.core.DictValue;

public class DictLabelTag extends TagSupport {

    private String dictName = "";
    private String itemCode;

    public String getDictName() {
        return dictName;
    }

    public void setDictName(String dictName) {
        this.dictName = dictName;
    }

    public String getItemCode() {
        return itemCode;
    }

    public void setItemCode(String itemCode) {
        this.itemCode = itemCode;
    }

    @Override
    public int doEndTag() throws JspException {
        DictValue dict = new DictValue();
        JspWriter out = pageContext.getOut();
        try {
            out.write(dict.codeToName(getDictName(),getItemCode()));
        } catch (IOException e) {
            throw new JspException(e);
        }
        return TagSupport.EVAL_PAGE;
    }
}

4.接下来配置tld文件，代码如下：dict.tld:

<?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>SPay JSP Form Tag Library</description>
    <tlib-version>1.0</tlib-version>
    <short-name>dict</short-name>
    <uri>http://www.tljc.com/dict_tag</uri>

    <tag>
        <description>Renders an HTML 'select' element. Supports databinding to the selected option.</description>
        <name>select</name>
        <tag-class>com.infopatent.juangetljc.web.controller.core.DictSelectTag</tag-class>
        <body-content>JSP</body-content>
        <attribute>  
               <name>defaultValue</name>  
            <required>true</required>  
            <rtexprvalue>true</rtexprvalue>  
        </attribute>  
    <attribute>  
            <name>value</name>  
            <required>false</required>  
            <rtexprvalue>true</rtexprvalue>  
    </attribute>
    <attribute>
        <name>dictName</name>
        <required>true</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>name</name>
        <required>true</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>id</name>
        <required>true</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>cssClass</name>
        <required>false</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>styleClass</name>
        <required>false</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>multiple</name>
        <required>false</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
        <name>onChange</name>
        <required>false</required>  
        <rtexprvalue>true</rtexprvalue>
    </attribute>
    </tag>

    <tag>
        <name>itemdesc</name>
        <tag-class>com.infopatent.juangetljc.web.controller.core.DictLabelTag</tag-class>
        <body-content>JSP</body-content>
        <attribute>
            <description>The Dict Name config in dict_value</description>
            <name>dictName</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
        <attribute>
            <description>The Dict Code config in dict_value</description>
            <name>itemCode</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
    </tag>
</taglib>

5.接下来在jsp页面里引入标签：

<%@taglib prefix="dict" uri="http://www.tljc.com/dict_tag" %>

这样便可以在jsp页面里使用定义的标签了：

<dict:select defaultValue="true" name="GJ" id="GJ" dictName="GJ" cssClass="form-control"/>

前提是要在字典表里加上“GJ”这条数据。