ssm redis 数据字典在J2EE中的多种应用与实现

Posted 2020-10-08 风间影月の技术小站

数据字典在项目中是不可缺少的“基础设施”，关于数据字典如何设计如何实现，今天抽空讲一下吧

先看一下表设计：

通过自定义标签来实现页面的渲染：

public class DataDictValueTag extends SimpleTagSupport {

    private String typeCode;

    private String ddKey;
    
    StringWriter sw = new StringWriter();
    
    public void doTag() throws JspException, IOException {
        if (StringUtils.isNotEmpty(typeCode) && StringUtils.isNotEmpty(ddKey)) {
            
            DataDictService ddService = (DataDictService)SpringContextUtil.getBean(DataDictService.class);
            String ddValue = ddService.queryDataDictValueByCodeKey(typeCode, ddKey);
            
            JspWriter out = getJspContext().getOut();
            out.println(ddValue);
        } else {
            getJspBody().invoke(sw);
            getJspContext().getOut().println(sw.toString());
        }
    }

    public String getTypeCode() {
        return typeCode;
    }

    public void setTypeCode(String typeCode) {
        this.typeCode = typeCode;
    }

    public String getDdKey() {
        return ddKey;
    }

    public void setDdKey(String ddKey) {
        this.ddKey = ddKey;
    }

}

再看一下service，根据字典码和数据字典key来获取具体的值：

需要注意的是数据字典属于静态数据，要放到redis中

@Override
    public String queryDataDictValueByCodeKey(String typeCode, String ddKey) {
        String redisKey = "redis_datadict:" + typeCode + ":" + ddKey;
        // 从缓存中获取数据字典的值，如果没有该值，则从数据库中获取，最后再存入redis中
        String redisDdvalue = jedis.get(redisKey);
        if (StringUtils.isNotEmpty(redisDdvalue)) {
            return redisDdvalue;
        }
        
        DataDictExample dataDictExample = new DataDictExample();
        Criteria dataDictCriteria = dataDictExample.createCriteria();
        dataDictCriteria.andTypeCodeEqualTo(typeCode);
        dataDictCriteria.andDdkeyEqualTo(ddKey);
        dataDictCriteria.andIsShowEqualTo(YesOrNo.YES.value);
        List<DataDict> list = dataDictMapper.selectByExample(dataDictExample);
        if (list != null && list.size() > 0) {
            DataDict dd = (DataDict)list.get(0);
            
            String ddvalue = dd.getDdvalue();
            // 在Redis中设置数据字典的值
            jedis.set(redisKey, ddvalue);
            
            return ddvalue;
        }
        
        return "";
    }

再JSP中的使用：

<label>
                                                <input type="radio" name="sex" class="icheck" value="0" /> <dataDict:dataDictValue typeCode="sex" ddKey="0"/>
                                            </label>
                                            
                                            <label>
                                                <input type="radio" name="sex" class="icheck" value="1" /> <dataDict:dataDictValue typeCode="sex" ddKey="1"/>
                                            </label>
                                             
                                            <label>
                                                <input type="radio" name="sex" class="icheck" value="2" checked="checked"/> <dataDict:dataDictValue typeCode="sex" ddKey="2"/>
                                            </label>

如果是用jqgrid类似这样的js插件来渲染的话，那么需要再额外自定义api接口供js或者其他应用调用：

{ name: \'sex\', index: \'sex\', width: 20, sortable: false,
                    formatter:function(cellvalue, options, rowObject) {
                        
                        var typeCode = "sex";
                        var ddkey = cellvalue;
                        var ddvalue = "";
                        
                        $.ajax({
                            url: $("#hdnContextPath").val() + "/dataDict/queryDataDictValue.action",
                            type: "POST",
                            async: false,
                            data: {"typeCode": typeCode, "ddkey": ddkey},
                            success: function(data) {
                                if(data.status == 200 && data.msg == "OK") {
                                    ddvalue = data.data;
                                } else {
                                    console.log(JSON.stringify(data));
                                }
                            },
                            error: function (response, ajaxOptions, thrownError) {
                                Error.displayError(response, ajaxOptions, thrownError);                
                            }
                        });
                        
                        return ddvalue}  
                },

基本上就是这些用法了，具体我录制了一些视频，代码也上传到了github
http://www.itzixi.com/course/detail.shtml?courseId=17092078Y3009WX4

https://github.com/leechenxiang/LeeCX