jsp类:

<form action=""name="form3">
<table class="ta">
<tr>
<td>部门：
<select name="branch"id="branch">
<option >请选择</option>
<option value="人事部">人事部</option>
<option value="财务部">财务部</option>
<option value="后勤部">后勤部</option>
</select>
</td>
<td>开始时间：<input type="date" id="st"name="startDate"value="${startDate}"pattern="yyyy-MM-dd"/>
</td>
<td>至</td>
<td>结束时间：<input type="date" id="en"name="endDate"value="${endDate}"pattern="yyyy-MM-dd"/></td>
<td><input type="button" value="查询"type="submit" onclick="form3.action='findByBranchAndDate';form3.submit();""/></td>
</tr>
</table>

action类：
public String getStartDate() {
return startDate;
}

public String getEndDate() {
    return endDate;
}

public String getBranch() {
    return branch;
}

public void setBranch(String branch) {
this.branch = branch;
}

public void setStartDate(String startDate) {
    this.startDate = startDate;
}

public void setEndDate(String endDate) {
    this.endDate = endDate;
}

public String findByBranchAndDate() {

    Date start=Date.valueOf(startDate);
    Date end=Date.valueOf(endDate);
   this.signInfos=signInfoService.findByBranch(branch, start, end);
    return SUCCESS;

}