mybatis动态增删改查

      原来使用sql时也都只是DML（Data Manipulation Language 数据操控语言）的，对于DDL（Data Definition Language 数据定义语言）的操作比较少涉及，最近项目中恰巧需要进行DDL操作，进行简单的记录。项目需求，根据前台传来的表名，字段，数据，进行动态的创建表格，实现对表格的增删改查操作。

    首先创建一个实体类，用来封装操作表的数据。

/**
 * 
 * @Description :动态操作表变量
 * @author Bush罗
 * @date 2018年7月19日
 *
 */
public class OperateTable {
	//表名
	private String tableName;
	//用于添加字段使用
	private String wordSegment;
	//用于创建数据库时使用，存放所有需要的字段
	private List<String> listWord;
	//字段所表示的中文意思，需要从前台传过来
	private List<String> listWordMean;
	//用于删除数据使用的id
	private Integer id;
	//表示一行数据，用户填写的一行数据
	private List<String> listData;
	//返回该数据库的所有表明
	private List<String> listTableName;
	//存放字段和数据
	private Map<String,String> mapWordData;

dao层接口

public interface OperateTableService {
	// 创建表
	void createTable(OperateTable operateTable);

	// 插入数据
	void insertTable(OperateTable operateTable);

	// 查找所有表名
	List<TableName> findAllTableName();

	// 更新数据库
	void updateTable(@Param("content") Map<String, String> mapWordData);

	// 更新数据库
	void updateTable1(OperateTable operateTable);

	// 动态删除数据
	void deleteById(OperateTable operateTable);

	// 动态为表添加字段
	void addColumn(OperateTable operateTable);
}

最重要的动态sql语句，也是mybatis最大的优点，灵活

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.smxy.lq.dao.OperateTableMapper">
	<!--创建一个以id为主键的自增表 -->
	<!-- 1.ddl使用update标签 -->
	<!-- 2.ddl使用${}取值 -->
	<!-- 3.动态列实际上只是普通的foreach, 常见问题是使用#{}取值造成语法错误 -->
	<update id="createTable" parameterType="com.smxy.lq.pojo.OperateTable">
		create table ${tableName} (
		id int(100) NOT NULL PRIMARY KEY
		AUTO_INCREMENT,
		<foreach collection="listWord" item="word" separator=",">
			${word}
			varchar(255)
		</foreach>
		) ENGINE=InnoDB DEFAULT CHARSET=utf8
	</update>
	<insert id="insertTable" parameterType="com.smxy.office.pojo.OperateTable">
		<!-- 将插入数据的主键返回，返回到对象中 SELECT LAST_INSERT_ID()：得到刚insert进去记录的主键值，只适用与自增主键 
			keyProperty：将查询到主键值设置到parameterType指定的对象的哪个属性 order：SELECT LAST_INSERT_ID()执行顺序，相对于insert语句来说它的执行顺序 
			resultType：指定SELECT LAST_INSERT_ID()的结果类型 -->
		<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
			SELECT
			LAST_INSERT_ID()
		</selectKey>
		insert into
		${tableName}
		<trim prefix="(" suffix=")" suffixOverrides=",">
			<foreach collection="mapWordData.keys" item="key" open=""
				close="" separator=",">
				${key}
			</foreach>
		</trim>
		<trim prefix="values (" suffix=")" suffixOverrides=",">
			<foreach collection="mapWordData.values" item="value"
				separator=",">
				#{value}
			</foreach>
		</trim>
	</insert>
	<!--查找所有数据库的表的名字 -->
	<select id="findAllTableName" resultType="com.smxy.lq.pojo.TableName">
		select
		table_name
		FROM
		information_schema.tables
		WHERE table_schema = 'market'
		AND table_type =
		'base table'
		AND TABLE_NAME LIKE "office_%"
	</select>
	<!--动态更新数据库 -->
	<update id="updateTable" parameterType="java.util.Map">
		update office_1 SET
		<foreach collection="content.keys" item="key" open="" close=""
			separator=",">
			${key} = #{content[${key}]}
		</foreach>
		where id = 1
	</update>
	<!-- 动态更新数据库 -->
	<update id="updateTable1" parameterType="com.smxy.office.pojo.OperateTable">
		update ${tableName}
		<set>
			<foreach item="value" index="key" collection="mapWordData.entrySet()"
				open="" close="" separator=",">
				${key}=#{value}
			</foreach>
		</set>
		where id = #{id}
	</update>
	<!--动态删除数据 -->
	<delete id="deleteById" parameterType="com.smxy.lq.pojo.OperateTable">
		delete from ${tableName}
		where id = #{id}
	</delete>
	<!--动态为表增加字段  -->
	<update id="addColumn" parameterType="com.smxy.lq.pojo.OperateTable">
		alter table ${tableName} add column ${wordSegment} varchar(255);
	</update>
</mapper>

Controller测试用例

/**
 * 
 * @Description :动态操作数据库案例
 * @author Bush罗
 * @date 2018年7月20日
 *
 */
@Controller
public class OperateTableController {
	
	@Autowired
	private OperateTableService operateTableService;

	@ResponseBody
	@RequestMapping("/creat")
	public String creat() {
		System.out.println("创建");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		List<String> list = new LinkedList<String>();
		list.add("of_1");
		list.add("of_2");
		list.add("of_3");
		operateTable.setListWord(list);
		operateTableService.createTable(operateTable);
		return "创建成功";
	}
	@ResponseBody
	@RequestMapping("/insertTable")
	public String insertTable() {
		System.out.println("插入");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		Map<String,String> mapWordData=new HashMap<String,String>();
		mapWordData.put("username", "小红");
		mapWordData.put("sex", "男");
		mapWordData.put("phonenumber", "123456789");
		mapWordData.put("teacherid", "500");
		operateTable.setMapWordData(mapWordData);
		operateTableService.insertTable(operateTable);
		return "success";
	}
	
	@ResponseBody
	@RequestMapping("/updateTable")
	public String updateTable() {
		System.out.println("更新");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		Map<String,String> mapWordData=new HashMap<String,String>();
		mapWordData.put("of_1", "小红");
		mapWordData.put("of_2", "明");
		mapWordData.put("of_3", "500");
		operateTable.setMapWordData(mapWordData);
		System.out.println(operateTable.toString());
		operateTableService.updateTable(mapWordData);
		return "更新成功";
	}
	@ResponseBody
	@RequestMapping("/updateTable1")
	public String updateTable1() {
		System.out.println("更新1");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		Map<String,String> mapWordData=new HashMap<String,String>();
		mapWordData.put("of_1", "6红");
		mapWordData.put("of_2", null);
		mapWordData.put("of_3", "小芳");
		operateTable.setMapWordData(mapWordData);
		operateTable.setId(3);
		operateTableService.updateTable1(operateTable);
		return "更新成功1";
	}
	@ResponseBody
	@RequestMapping("delete")
	public String delete(){
		System.out.println("删除");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		operateTable.setId(3);
		operateTableService.deleteById(operateTable);
		return "删除成功";
	}
	@ResponseBody
	@RequestMapping("addcolumn")
	public String addcolumn(){
		System.out.println("添加字段");
		OperateTable operateTable = new OperateTable();
		operateTable.setTableName("office_1");
		operateTable.setWordSegment("of_4");
		operateTableService.deleteById(operateTable);
		return "添加成功";
	}
	

}