LayUI第三方组件TreeSelect下拉树实现详解

<input type="text" name="parentId" id="tree2" lay-filter="tree2" class="layui-input" />

<script type="text/javascript">
    layui.use(["treeSelect", "form", "tree"], function () {
        var form = layui.form;
        var tree = layui.tree;
        var treeSelect = layui.treeSelect;
        treeSelect.render({
            // 选择器
            elem: '#tree',
            // 异步获取下拉树需要显示的数据
            data: 'dept/treeSelect',
            // 异步加载方式：get/post，默认get
            type: 'post',
            // 占位符
            placeholder: '上级菜单',
            // 是否开启搜索功能：true/false，默认false
            search: true,
            // 一些可定制的样式
            style: {
                folder: {
                    enable: true
                },
                line: {
                    enable: true
                }
            },
            // 点击节点回调
            click: function(d){
                //console.log(d);
            },
            // 加载完成后的回调函数
            success: function (d) {
                //console.log(d);
                // 选中节点，根据id筛选，一般修改时会有默认选中状态，可以在这里设置
                //treeSelect.checkNode('tree', 2);
                //console.log($('#tree').val());
                // 获取zTree对象，可以调用zTree方法
                //var treeObj = treeSelect.zTree('tree');
                // console.log(treeObj);
                // 刷新树结构
                //treeSelect.refresh('tree');
            }
        });
    });
 
</script>

@RequestMapping(value="/treeSelect")
@ResponseBody
//这里写的，新增和修改数据请求都是同一个方法，如果是修改会传递一个修改对象的id
public Object treeSelect(Integer id) {
    Sort sort = Sort.by("idx");    //排序
    Specification<Dept> spec = buildSpec1();    //查询条件，查询父节点为null的元素
    List<Dept> list = deptService.findAll(spec,sort);    //查询，Dept为实体类
    return buildTree(list, id);    //转换为treeSelect指定的JSON数据格式方法
}
 
private Object buildTree(List<Dept> list, Integer id) {
    List<HashMap<String, Object>> result=new ArrayList<>();
    for (Dept dept : list) {
        if(dept.getId() != id) {    //判断如果是修改的话，修改的节点及下级节点不显示，也就不加载
            HashMap<String, Object> node=new HashMap<>();
            node.put("id", dept.getId());    //节点id
            node.put("name",dept.getName());    //节点数据名称
            node.put("open", false);        //是否展开
            node.put("checked", false);    //是否选中，前台也可以设置是否选中
            if(dept.getChildren().size() != 0) {    //如果下级节点不为空，
                node.put("children",buildTree(dept.getChildren(), id));    //递归加载下级节点
            }
            result.add(node);
        }
    }
    return result;
}
 
public Specification<Dept> buildSpec1() {
    Specification<Dept> specification = new Specification<Dept>() {
 
        private static final long serialVersionUID = 1L;
 
        @Override
        public Predicate toPredicate(Root<Dept> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
            HashSet<Predicate> rules=new HashSet<>();
            Predicate parent = cb.isNull(root.get("parent"));  //查询父节点为null的元素
            rules.add(parent);
            return cb.and(rules.toArray(new Predicate[rules.size()]));
        }
 
    };
    return specification;
}

import com.fasterxml.jackson.annotation.JsonIgnore;
import org.springframework.data.annotation.CreatedBy;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;
 
@Entity
public class Dept {
    private Integer id;
    private String name;    //部门名称
    private String deptName;    //部门负责人
    private String phone;   //电话号
    private String number;  //编号
    private double idx;     //排序
    @JsonIgnore
    private Dept parent;
    @JsonIgnore
    private List<Dept> children = new ArrayList<>();
 
    @Id
    @GeneratedValue
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public String getDeptName() {
        return deptName;
    }
 
    public void setDeptName(String deptName) {
        this.deptName = deptName;
    }
 
    public String getPhone() {
        return phone;
    }
 
    public void setPhone(String phone) {
        this.phone = phone;
    }
 
    public String getNumber() {
        return number;
    }
 
    public void setNumber(String number) {
        this.number = number;
    }
 
    public double getIdx() {
        return idx;
    }
 
    public void setIdx(double idx) {
        this.idx = idx;
    }
 
    @ManyToOne
    @CreatedBy
    public Dept getParent() {
        return parent;
    }
 
    public void setParent(Dept parent) {
        this.parent = parent;
    }
 
    @OneToMany(cascade=CascadeType.ALL,mappedBy="parent")
    @OrderBy(value="idx")
    public List<Dept> getChildren() {
        return children;
    }
 
    public void setChildren(List<Dept> children) {
        this.children = children;
    }
 
    public Dept(Integer id, String name, String deptName, String phone, String number, double idx, Dept parent, List<Dept> children) {
        this.id = id;
        this.name = name;
        this.deptName = deptName;
        this.phone = phone;
        this.number = number;
        this.idx = idx;
        this.parent = parent;
        this.children = children;
    }
 
    public Dept(Integer id) {
        this.id = id;
    }
 
    public Dept() {
    }
}

[
	{
		"children": [	//下级节点
			{
				"children": [
					{
						"name": "测试",
						"checked": false,
						"id": 30,
						"open": false
					}, {
						"name": "开发",
						"checked": false,
						"id": 31,
						"open": false
					}, {
						"children": [
							{
								"name": "测试节点",
								"checked": false,
								"id": 36,
								"open": false
							}
						],
						"name": "测试",
						"checked": false,
						"id": 32,
						"open": false
					}
				],
				"name": "技术部",
				"checked": false,
				"id": 2,
				"open": false
			}, {
				"name": "财务部",
				"checked": false,
				"id": 19,
				"open": false
			}
		],
		"name": "某某公司",	//节点内容
		"checked": false,	//是否选中
		"id": 1,		//id
		"open": false	//是否展开
	}, {
		"name": "测试",
		"checked": false,
		"id": 33,
		"open": false
	}
]