大家都知道Javabean+servlet+JSP是最简单的MVC模式。的确，在一个小型的项目中，这个模式完全够用。
它优雅并且简洁。加上jQueryui的完美展示效果，让这个模式看起来非常合适。当然这其中必不可少的是ajax和json格式的应用。
1、首先从数据库(sqlserver)中获取结果集并封装到Javabean中。在此之前要定义你所需要的bean类。
/*
* 查询Branch
*/
public ArrayList<Branch> selBranch(Connection connection){
Branch branch=null;
ArrayList<Branch> list=new ArrayList<Branch>();
if (connection == null) {
return null;
}
String sql="select distinct mb.BRANCH_CD,mb.BRANCH_NM from BRANCH mb";
try {
PreparedStatement ps=connection.prepareStatement(sql);
ResultSet rs=ps.executeQuery();
while(rs.next()){
branch =new Branch();
branch.setBranchCD(rs.getInt(1));
branch.setBranchName(rs.getString(2));
list.add(branch);
}
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
try {
connection.close();
connection = null;
} catch (SQLException e) {
e.printStackTrace();
}
}
return list; }
2、然后创建Servlet
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
} /**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/json; charset=utf-8");
SqlHandleTool sqlHandleTool=new SqlHandleTool();
SqlConnectTool connection=new SqlConnectTool();
ArrayList<Branch> list = sqlHandleTool.selBranch(connection.getSql2008Connection());
JSONArray jsonArray=JSONArray.fromObject(list);
PrintWriter out = response.getWriter();
out.println(jsonArray);
}
3、最后在js中应用ajax
function loadBranch(){
$.ajax({
url: "BranchsList.do",
dataType:"json",
//async: false,
success:function(data){
var options = [];
for(var i=0;i<data.length;i++){
options.push('<option value="' + data[i].branchCD + '">'
+ data[i].branchName + '</option>');
}
$("#sel5").empty()
.html(options.join(""))
.attr("loaded", true);
count++;
exec();
},
error:function(){
}
});
}