如何使用Spring在Postgresql中存储java.util.ArrayList

Question

我正在尝试批量插入一组bean.bean的一个属性是ArrayList.批量更新失败,但出现异常:

 Can't infer the SQL type to use for an instance of java.util.ArrayList. Use setObject() with an explicit Types value to specify the type to use.

我不知道使用哪个Postgresql数据类型与ArrayList兼容.有没有办法可以在不更改其属性的数据类型的情况下批量更新bean？

---

豆子:

    import java.util.List;

    public class SomeBean {
        private int id;
        private List<String> names;

        @Override
        public String toString() {
            return "SomeBean [id=" + id + ", names=" + names + "]";
        }
        //Setters and getters

表模式:

CREATE TABLE arraylistexample
(
  id serial NOT NULL,
  names character varying[]
)

插入数据的方法:

    public void insert(List<SomeBean> beans){
        String sql = "INSERT INTO ARRAYLISTEXAMPLE (NAMES) VALUES (:names)";

        SqlParameterSource[] data = SqlParameterSourceUtils.createBatch(beans.toArray());
        pgTemplate.batchUpdate(sql, data);
    }

例外:

Exception in thread "main" org.springframework.jdbc.BadSqlGrammarException: PreparedStatementCallback; bad SQL grammar [INSERT INTO ARRAYLISTEXAMPLE (NAMES) VALUES (?, ?)]; nested exception is org.postgresql.util.PSQLException: Can't infer the SQL type to use for an instance of java.util.ArrayList. Use setObject() with an explicit Types value to specify the type to use.
    at org.springframework.jdbc.support.SQLStateSQLExceptionTranslator.doTranslate(SQLStateSQLExceptionTranslator.java:98)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:603)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:615)
    at org.springframework.jdbc.core.JdbcTemplate.batchUpdate(JdbcTemplate.java:884)
    at org.springframework.jdbc.core.namedparam.NamedParameterBatchUpdateUtils.executeBatchUpdateWithNamedParameters(NamedParameterBatchUpdateUtils.java:40)
    at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.batchUpdate(NamedParameterJdbcTemplate.java:303)
    at some.package.dao.GenericDao.insert(GenericDao.java:45)
    at some.package.runner.FileLogicTester.storingArrayListInDb(FileLogicTester.java:220)
    at some.package.runner.FileLogicTester.main(FileLogicTester.java:86)
Caused by: org.postgresql.util.PSQLException: Can't infer the SQL type to use for an instance of java.util.ArrayList. Use setObject() with an explicit Types value to specify the type to use.
    at org.postgresql.jdbc2.AbstractJdbc2Statement.setObject(AbstractJdbc2Statement.java:1801)
    at org.postgresql.jdbc3g.AbstractJdbc3gStatement.setObject(AbstractJdbc3gStatement.java:37)
    at org.postgresql.jdbc4.AbstractJdbc4Statement.setObject(AbstractJdbc4Statement.java:46)
    at org.apache.commons.dbcp.DelegatingPreparedStatement.setObject(DelegatingPreparedStatement.java:255)
    at org.springframework.jdbc.core.StatementCreatorUtils.setValue(StatementCreatorUtils.java:351)
    at org.springframework.jdbc.core.StatementCreatorUtils.setParameterValueInternal(StatementCreatorUtils.java:216)
    at org.springframework.jdbc.core.StatementCreatorUtils.setParameterValue(StatementCreatorUtils.java:144)
    at org.springframework.jdbc.core.BatchUpdateUtils.setStatementParameters(BatchUpdateUtils.java:63)
    at org.springframework.jdbc.core.namedparam.NamedParameterBatchUpdateUtils.access$000(NamedParameterBatchUpdateUtils.java:32)
    at org.springframework.jdbc.core.namedparam.NamedParameterBatchUpdateUtils$1.setValues(NamedParameterBatchUpdateUtils.java:47)
    at org.springframework.jdbc.core.JdbcTemplate$4.doInPreparedStatement(JdbcTemplate.java:893)
    at org.springframework.jdbc.core.JdbcTemplate$4.doInPreparedStatement(JdbcTemplate.java:884)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:587)
    ... 7 more

有什么建议？

Answer 1

我认为 PGSQL 的数据类型不正确，请参考 此

character Varvar(n) varchar(n) 变长字符串

您可能正在寻找的是 PGSQL 数组