使用mybatis的时候遇到关联问题。
可以参考如下:
一个自关联的model
public class TreeDic implements java.io.Serializable{ private static final long serialVersionUID = 5454155825314635342L; //alias public static final String TABLE_ALIAS = "树形树形字典"; public static final String ALIAS_ID = "编号"; public static final String ALIAS_PARENT_ID = "父节点编号"; public static final String ALIAS_PARENT_IDS = "所有父节点编号"; public static final String ALIAS_TYPE = "分类"; public static final String ALIAS_CODE = "键值"; public static final String ALIAS_NAME = "标签"; public static final String ALIAS_REMARKS = "描述"; public static final String ALIAS_SORT = "排序"; public static final String ALIAS_DEL_FLAG = "del_flag"; public static final String ALIAS_VERSION = "version"; //date formats private TreeDic parent; private List<TreeDic> childList = Lists.newArrayList(); //可以直接使用: @Length(max=50,message="用户名长度不能大于50")显示错误消息 //columns START /** * id db_column: id */ @Max(9223372036854775807L) private java.lang.Long id; /** * parent_id db_column: parent_id */ @NotNull @Max(9223372036854775807L) private java.lang.Long parentId; /** * parent_ids db_column: parent_ids */ @NotBlank @Length(max=255) private java.lang.String parentIds; /** * type db_column: type */ @Length(max=100) private java.lang.String type; /** * code db_column: code */ @Length(max=100) private java.lang.String code; /** * name db_column: name */ @Length(max=100) private java.lang.String name; /** * remarks db_column: remarks */ @Length(max=255) private java.lang.String remarks; /** * sort db_column: sort */ @Max(9999999999L) private java.lang.Integer sort; /** * del_flag db_column: del_flag */ @Length(max=1) private java.lang.String delFlag; /** * version db_column: version */ @Max(9999999999L) private java.lang.Integer version; //columns END public TreeDic(){ this.delFlag = "0"; this.version = 1; } public TreeDic( java.lang.Long id ){ this.id = id; } public void setId(java.lang.Long value) { this.id = value; } public java.lang.Long getId() { return this.id; } public void setParentId(java.lang.Long value) { this.parentId = value; } public java.lang.Long getParentId() { return this.parentId; } public void setParentIds(java.lang.String value) { this.parentIds = value; } public java.lang.String getParentIds() { return this.parentIds; } public void setType(java.lang.String value) { this.type = value; } public java.lang.String getType() { return this.type; } public void setCode(java.lang.String value) { this.code = value; } public java.lang.String getCode() { return this.code; } public void setName(java.lang.String value) { this.name = value; } public java.lang.String getName() { return this.name; } public void setRemarks(java.lang.String value) { this.remarks = value; } public java.lang.String getRemarks() { return this.remarks; } public void setSort(java.lang.Integer value) { this.sort = value; } public java.lang.Integer getSort() { return this.sort; } public void setDelFlag(java.lang.String value) { this.delFlag = value; } public java.lang.String getDelFlag() { return this.delFlag; } public void setVersion(java.lang.Integer value) { this.version = value; } public java.lang.Integer getVersion() { return this.version; } /** * @return Returns the parent. */ public TreeDic getParent() { return parent; } /** * @param parent The parent to set. */ public void setParent(TreeDic parent) { this.parent = parent; } /** * @return Returns the childList. */ public List<TreeDic> getChildList() { return childList; } /** * @param childList The childList to set. */ public void setChildList(List<TreeDic> childList) { this.childList = childList; } public static void sortList(List<TreeDic> list, List<TreeDic> sourcelist, Long parentId){ for (int i=0; i<sourcelist.size(); i++){ TreeDic e = sourcelist.get(i); if (e.getParent()!=null && e.getParent().getId()!=null && e.getParent().getId().equals(parentId)){ list.add(e); // 判断是否还有子节点, 有则继续获取子节点 for (int j=0; j<sourcelist.size(); j++){ TreeDic childe = sourcelist.get(j); if (childe.getParent()!=null && childe.getParent().getId()!=null && childe.getParent().getId().equals(e.getId())){ sortList(list, sourcelist, e.getId()); break; } } } } } public boolean isRoot(){ return isRoot(this.id); } public static boolean isRoot(Long id){ return id != null && id.equals(1L); } public String toString() { return ToStringBuilder.reflectionToString(this); } public int hashCode() { return new HashCodeBuilder() .append(getId()) .toHashCode(); } public boolean equals(Object obj) { if(obj instanceof TreeDic == false) return false; if(this == obj) return true; TreeDic other = (TreeDic)obj; return new EqualsBuilder() .append(getId(),other.getId()) .isEquals(); } }
Mapper文件的配置很重要:
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> <!-- 不使用namespace的话sql搜索定位会比较方便 --> <mapper namespace="TreeDic"> <resultMap id="RM.TreeDic" type="net.cciot.snail.sys.model.TreeDic"> <result property="id" column="id"/> <result property="parentId" column="parent_id"/> <result property="parentIds" column="parent_ids"/> <result property="type" column="type"/> <result property="code" column="code"/> <result property="name" column="name"/> <result property="remarks" column="remarks"/> <result property="sort" column="sort"/> <result property="delFlag" column="del_flag"/> <result property="version" column="version"/> <!-- 查询父模块 --> <association property="parent" column="parent_id" select="TreeDic.getById" /> <!-- 查询子模块 --> <collection property="childList" column="id" select="TreeDic.getChildList" /> </resultMap> <!-- 用于select查询公用抽取的列 --> <sql id="TreeDic.columns"> <![CDATA[ id,parent_id,parent_ids,type,code,name,remarks,sort,del_flag,version ]]> </sql> <!-- useGeneratedKeys="true" keyProperty="xxx" for sqlserver and mysql --> <insert id="TreeDic.insert" useGeneratedKeys="true" keyProperty="id"> <![CDATA[ INSERT INTO sys_tree_dic ( id, parent_id, parent_ids, type, code, name, remarks, sort, del_flag, version ) VALUES ( #{id}, #{parentId}, #{parentIds}, #{type}, #{code}, #{name}, #{remarks}, #{sort}, #{delFlag}, #{version} ) ]]> <!-- oracle: order="BEFORE" SELECT sequenceName.nextval AS ID FROM DUAL DB2: order="BEFORE"" values nextval for sequenceName <selectKey resultType="java.lang.Long" order="BEFORE" keyProperty="userId"> SELECT sequenceName.nextval AS ID FROM DUAL </selectKey> --> </insert> <update id="TreeDic.update" > <![CDATA[ UPDATE sys_tree_dic SET parent_id = #{parentId} , parent_ids = #{parentIds} , type = #{type} , code = #{code} , name = #{name} , remarks = #{remarks} , sort = #{sort} , del_flag = #{delFlag} , version = version + 1 WHERE id = #{id} ]]> </update> <delete id="TreeDic.delete"> <![CDATA[ UPDATE sys_tree_dic SET del_flag = '1' WHERE id = #{id} ]]> </delete> <select id="TreeDic.getById" resultMap="RM.TreeDic"> SELECT <include refid="TreeDic.columns" /> <![CDATA[ FROM sys_tree_dic WHERE id = #{id} ]]> </select> <select id="TreeDic.getChildList" resultMap="RM.TreeDic"> SELECT <include refid="TreeDic.columns" /> <![CDATA[ FROM sys_tree_dic WHERE parent_id = #{id} ]]> </select> <sql id="TreeDic.findPage.where"> <!-- ognl访问静态方法的表达式 为@class@method(args),以下为调用rapid中的Ognl.isNotEmpty()方法,还有其它方法如isNotBlank()可以使用,具体请查看Ognl类 --> <where> <if test="@Ognl@isNotEmpty(id)"> AND id = #{id} </if> <if test="@Ognl@isNotEmpty(parentId)"> AND parent_id = #{parentId} </if> <if test="@Ognl@isNotEmpty(parentIds)"> AND parent_ids = #{parentIds} </if> <if test="@Ognl@isNotEmpty(type)"> AND type = #{type} </if> <if test="@Ognl@isNotEmpty(code)"> AND code = #{code} </if> <if test="@Ognl@isNotEmpty(name)"> AND name = #{name} </if> <if test="@Ognl@isNotEmpty(remarks)"> AND remarks = #{remarks} </if> <if test="@Ognl@isNotEmpty(sort)"> AND sort = #{sort} </if> <if test="@Ognl@isNotEmpty(delFlag)"> AND del_flag = #{delFlag} </if> <if test="@Ognl@isNotEmpty(version)"> AND version = #{version} </if> </where> </sql> <select id="TreeDic.findPage.count" resultType="long"> SELECT count(*) FROM sys_tree_dic <include refid="TreeDic.findPage.where"/> </select> <!-- 分页查询已经使用Dialect进行分页,也可以不使用Dialect直接编写分页 因为分页查询将传 offset,pageSize,lastRows 三个参数,不同的数据库可以根于此三个参数属性应用不同的分页实现 --> <select id="TreeDic.findPage" resultMap="RM.TreeDic"> SELECT <include refid="TreeDic.columns" /> FROM sys_tree_dic <include refid="TreeDic.findPage.where"/> <if test="@Ognl@isNotEmpty(sortColumns)"> ORDER BY ${sortColumns} </if> <if test="offset != null and pageSize != null" > <![CDATA[ limit #{offset} , #{pageSize} ]]> </if> </select> </mapper>
总结与此,方便下次使用