public class Student
{
 private String name;
 private String num;
}
StudentAction.java
public class StudentAction extends ActionSupport
{
 private List<Student> lstStu;
}

<script type="text/javascript">
 var stus = [];
 stus.push({num:"1",name:"xy1"});
 stus.push({num:"2",name:"xy2"});
 stus.push({num:"3",name:"xy3"});
</script>

var htmlContent = "";
for(var i=0;i<stus.length;i++){
 htmlContent += "<input type='hidden' name='lstStu[" + i + "].name' value='" + stus[i].name + " ' />";
 htmlContent += "<input type='hidden' name='lstStu[" + i + "].num' value='" + stus[i].num + " ' />";
}

<input type='hidden' name='lstStu.name' value='xy1' />
<input type='hidden' name='lstStu.name' value='xy2' />
<input type='hidden' name='lstStu.name' value='xy3' />

var param = {};
for(var i=0;i<stus.length;i++){
 param["lstStu[" + i + "].name"] = stus[i].name;
 param["lstStu[" + i + "].num"] = stus[i].num;
}
$.ajax({
 data:param
});

data:{
 lstStu[0].num:"1",lstStu[0].name:"xy1",
 lstStu[1].num:"2",lstStu[1].name:"xy2",
 lstStu[2].num:"3",lstStu[0].name:"xy3"
}