有 Java 编程相关的问题?

你可以在下面搜索框中键入要查询的问题!

java使用MyBatis和MySql以编程方式创建表

我想创建一个方法来动态创建表,只需将表名作为变量传递。 我已经定义了xml映射器

<mapper namespace="com.mappers.TableCreatorMapper">
    <cache />
    <insert id="createNewTableIfNotExists" parameterType="String" > 
        CREATE TABLE IF NOT EXISTS #{tableName} 
        (
        `ID` varchar(20) NOT NULL,
        PRIMARY KEY (`ID`)
        ) 
        ENGINE=InnoDB
    </insert>
</mapper>

我的Java接口映射器是:

public interface TableCreatorMapper {
     public void createNewTableIfNotExists(String tableName);
}

但是当我调用我的接口时

tableCreatorMapper.createNewTableIfNotExists("test");

我得到以下例外情况:

org.springframework.jdbc.BadSqlGrammarException: 
### Error updating database.  Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''test' 
        (
        `ID` varchar(20) NOT NULL,
        PRIMARY KEY (`ID`)
' at line 1
### The error may involve com.mappers.TableCreatorMapper.createNewTableIfNotExists-Inline
### The error occurred while setting parameters
### SQL: CREATE TABLE IF NOT EXISTS ?          (         `ID` varchar(20) NOT NULL,         PRIMARY KEY (`ID`)         )    ENGINE=InnoDB
### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''test' 
        (
        `ID` varchar(20) NOT NULL,
        PRIMARY KEY (`ID`)
' at line 1
; bad SQL grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''test' 
        (
        `ID` varchar(20) NOT NULL,
        PRIMARY KEY (`ID`)
' at line 1
    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:231)
    at org.sp

如果我改为更改查询,为表名添加“`”:

 CREATE TABLE IF NOT EXISTS `#{tableName}`(
        `ID` varchar(20) NOT NULL,
        PRIMARY KEY (`ID`)
        ) 
        ENGINE=InnoDB

我明白了

### The error occurred while setting parameters
### SQL: CREATE TABLE IF NOT EXISTS `?`(         `ID` varchar(20) NOT NULL,         PRIMARY KEY (`ID`)         )    ENGINE=InnoDB
### Cause: java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0).
; SQL []; Parameter index out of range (1 > number of parameters, which is 0).; nested exception is java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0).

知道为什么吗


共 (2) 个答案

  1. # 1 楼答案

    试一试

    CREATE TABLE IF NOT EXISTS ${_parameter} 
            (
            `ID` varchar(20) NOT NULL,
            PRIMARY KEY (`ID`)
            ) 
            ENGINE=InnoDB
    

    {name}用于PreparedStatement中的参数(请参见Parameters中的字符串替换

  2. # 2 楼答案

    在DAO中,使用注释@Param void createTableIfNotExist(@Param("uuid") String uuid);

    在映射器中,使用$

    <update id="createTableIfNotExist" parameterType="java.lang.String">
      CREATE TABLE IF NOT EXISTS `table_${uuid}` 
      (
            `id` bigint(18) NOT NULL,
            `info` varchar(18) NOT NULL,
            PRIMARY KEY (`id`)
      )
      ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='this table is generated by java code.'
    </update>
    

    <bind>也可以在MAPPER中使用