1、ul li的多级列表的html代码tree
2、利用jquery
<ul id="tt"></ul>
$('#tt').tree({
url:'tree_data.json' //会发送异步请求返回tree数据
});
tree实体类：
public class Tree {
private int id ;
private String name ;
private String url ;
private int checked ;
private String icon ;
private int parent_id ;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public int getChecked() {
return checked;
}
public void setChecked(int checked) {
this.checked = checked;
}
public String getIcon() {
return icon;
}
public void setIcon(String icon) {
this.icon = icon;
}
public int getParent_id() {
return parent_id;
}
public void setParent_id(int parent_id) {
this.parent_id = parent_id;
}
treeVO 返回jsontree格式，必须这种形式tree,才能渲染成树：
public class TreeVO {
private int id;
private String text;
private int parent_id;
private String icon ;
private String state ;
private Map<String,Object> map=new HashMap<String ,Object>(); //用个map接收自定义属性，必须map，转为json后，是{"a":"","b":..}这种格式，同时具有可扩展性
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
} public int getParent_id() {
return parent_id;
}
public void setParent_id(int parent_id) {
this.parent_id = parent_id;
}
public String getIcon() {
return icon;
}
public void setIcon(String icon) {
this.icon = icon;
} public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public Map<String, Object> getMap() {
return map;
}
public void setMap(Map<String, Object> map) {
this.map = map;
} }
import com.bjsxt.dto.TreeVO;
public interface TreeDao {
List<TreeVO> getTreeByParentId(String id);
}
public class TreeDaoImpl implements TreeDao {
@Override
public List<TreeVO> getTreeByParentId(String id) {
String sql;
if(id==null || id==""){ //刚开始页面加载完成之后，页面出现根节点，这时，前台不带参数id,只有点击closed的节点才会发送一个请求，携带id
int pid=;
sql ="select * from tree where parent_id ="+;
System.out.println(sql);
}else{
//点击这些关闭的节点时才会发送一个url，同时携带这个节点的id,为什么easyui树高效，dtree不行，dtree是一打开页面加载所有的节点，而easyUi是点击节点才会异步发送一个请求，获取该节点下直接子节点渲染成树
int pid=Integer.valueOf(id);
sql ="select * from tree where parent_id ="+pid;
System.out.println(sql);
}
Connection conn = DBUtils.createConn();
PreparedStatement ps = DBUtils.getPs(conn, sql);
try {
ResultSet rs = ps.executeQuery();
List<Tree> treeList =new ArrayList<Tree>();
while(rs.next()){
Tree tree=new Tree();
tree.setId(rs.getInt("id"));
tree.setChecked(rs.getInt("checked"));
tree.setIcon(rs.getString("icon"));
tree.setName(rs.getString("name"));
tree.setParent_id(rs.getInt("parent_id"));
tree.setUrl(rs.getString("url"));
treeList.add(tree);
}
List<TreeVO> treeVOlist = this.tochange(treeList);
System.out.println(treeList+"treelist");
return treeVOlist;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
private List<TreeVO> tochange(List<Tree> treeList){
List<TreeVO> treeVOlist =new ArrayList<TreeVO>();
for (Tree tree : treeList) {
TreeVO treeVO =new TreeVO();
treeVO.setId(tree.getId());
List<Tree> tls = this.distinguish(tree.getId());
if(tls.isEmpty()){
treeVO.setState("open");
}else{
treeVO.setState("closed");
}
treeVO.setIcon(tree.getIcon());
treeVO.setParent_id(tree.getParent_id());
treeVO.setText(tree.getName());
Map<String,Object> hashMap=new HashMap<String,Object>();
hashMap.put("url", "");
treeVO.setMap(hashMap);
treeVOlist.add(treeVO);
}
System.out.println(treeList+"treelist1");
return treeVOlist;
}
private List<Tree> distinguish(int id){//判断节点下面有没有子节点，有的话，下面的子节点不为空，没有的话就是叶子节点，这时会自动渲染成
String sql ="select * from tree where parent_id ="+id;
Connection conn = DBUtils.createConn();
PreparedStatement ps = DBUtils.getPs(conn, sql);
try {
ResultSet rs = ps.executeQuery();
List<Tree> treeList =new ArrayList<Tree>();
while(rs.next()){
Tree tree=new Tree();
tree.setId(rs.getInt("id"));
tree.setChecked(rs.getInt("checked"));
tree.setIcon(rs.getString("icon"));
tree.setName(rs.getString("name"));
tree.setParent_id(rs.getInt("parent_id"));
tree.setUrl(rs.getString("url"));
treeList.add(tree);
}
return treeList;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
@WebServlet("/tree")
public class Tree extends HttpServlet {
private static final long serialVersionUID = 1L;
private TreeDao treeDao =new TreeDaoImpl();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String method = request.getParameter("method");
if(method.equals("getTree")){
getTree(request,response);
}
}
private void getTree(HttpServletRequest request, HttpServletResponse response) {
String id = request.getParameter("id");
List<TreeVO> treeList=treeDao.getTreeByParentId(id);
response.setContentType("text/html;charset=utf-8");
try {
response.getWriter().write(JSONArray.fromObject(treeList).toString());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
下面的代码多余的：
不需要转化int,拼接的sql，就是按照就是按照int,如果用字符串还需要在sql中''
if(id==null || id==""){
int pid=; //不需要
sql ="select * from tree where parent_id ="+;
System.out.println(sql);
}else{
int pid=Integer.valueOf(id);//不需要
sql ="select * from tree where parent_id ="+pid;
System.out.println(sql);
}
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