How to perform batch update in Spring with a list of maps?

Question

New to Spring, I am trying to insert a List<Map<String, Object>> into a table. Until now I have been using the SqlParameterSource for batch update, which works fine when a java bean is supplied to them. Something like this:

    @Autowired
    private NamedParameterJDBCTemplate v2_template;

    public int[] bulkInsertIntoSiteTable(List<SiteBean> list){
            SqlParameterSource[] batch = SqlParameterSourceUtils
                    .createBatch(list.toArray());
            int[] updateCounts = v2_template
                    .batchUpdate(
                            "insert into sitestatus (website, status, createdby) values (:website, :status, :username)",
                            batch);

            return updateCounts;

        }

However, I tried the same technique with a list of maps in place of a bean, it failed (rightly so).

public int[] bulkInsertIntoSiteTable(List<Map<String, Object>> list){
        SqlParameterSource[] batch = SqlParameterSourceUtils
                .createBatch(list.toArray());
        int[] updateCounts = v2_template
                .batchUpdate(
                        "insert into sitestatus (website, status, createdby) values (:website, :status, :username)",
                        batch);

        return updateCounts;

    }

The above code failed with the following exception:

Exception in thread "main" org.springframework.dao.InvalidDataAccessApiUsageException: No value supplied for the SQL parameter 'website': Invalid property 'website' of bean class [org.springframework.util.LinkedCaseInsensitiveMap]: Bean property 'website' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
    at org.springframework.jdbc.core.namedparam.NamedParameterUtils.buildValueArray(NamedParameterUtils.java:322)
    at org.springframework.jdbc.core.namedparam.NamedParameterBatchUpdateUtils$1.setValues(NamedParameterBatchUpdateUtils.java:45)
    at org.springframework.jdbc.core.JdbcTemplate$4.doInPreparedStatement(JdbcTemplate.java:893)
    at org.springframework.jdbc.core.JdbcTemplate$4.doInPreparedStatement(JdbcTemplate.java:1)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:587)
    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 tester.utitlies.dao.VersionTwoDao.bulkInsertIntoSites(VersionTwoDao.java:21)
    at tester.utitlies.runner.Main.main(Main.java:28)

It fails as it considers the list to be a batch of beans, I guess. I cannot find a way to perform a batch update in Spring with a list of maps and using NamedParameterJDBCTemplate. Please advice.

Answer 1

As per Spring NamedParameterJDBCTemplate docs, found here, this method can be used for batch updating with maps.

int[] batchUpdate(String sql, Map<String,?>[] batchValues)

The real challange was to a get an array of Map<String, Object> from a corresponding List<Map<String, Object>>. I used the following code to get the array and perform the batch update.

public static Map<String, Object>[] getArrayData(List<Map<String, Object>> list){
        @SuppressWarnings("unchecked")
        Map<String, Object>[] maps = new HashMap[list.size()];

        Iterator<Map<String, Object>> iterator = list.iterator();
        int i = 0;
        while (iterator.hasNext()) {
            Map<java.lang.String, java.lang.Object> map = (Map<java.lang.String, java.lang.Object>) iterator
                    .next();
            maps[i++] = map;
        }

        return maps;
    }