Question

我正在尝试插入从Rest API检索到的JSON数据，该数据由Jackson使用POJO解析。我在基于以下代码行插入记录时得到空指针异常 preparedStatement = dbConnection.prepareStatement（insertTableSQL）;

请在这里建议我做错了什么？

 Connection dbConnection = null;
    PreparedStatement preparedStatement = null;

    String insertTableSQL = "INSERT INTO Test_Batch"
            + "((Account_ID, BestPractice_Source, Check_ID, Importance,Category,Last_BestPractices_Checked_Date,Last_BestPractices_Updated_Date))                                                                          VALUES" + "(?,?,?,?,?,?,?)";

    try {
        dbConnection = getDBConnection();
        preparedStatement = dbConnection.prepareStatement(insertTableSQL);

        dbConnection.setAutoCommit(false);
        ObjectMapper mapper=new ObjectMapper();
         JsonNode root =mapper.readTree(new RestClient().Json());
          ArrayNode BestPracticeChecks=(ArrayNode)root.path("BestPracticeChecks");
              Iterator<JsonNode> iterator =BestPracticeChecks.elements();   
              BestPracticeChecks bestPracticeChecksid =null;    
        while (iterator.hasNext()) {                                 
                      bestPracticeChecksid = mapper.readValue(iterator.next().traverse(), BestPracticeChecks.class);                      
                          preparedStatement.setInt(1, Account_ID);
                          preparedStatement.setString(2, "xyz");
                          preparedStatement.setInt(3, bestPracticeChecksid.getCheckId());
                          preparedStatement.setString(4, bestPracticeChecksid.getImportance());
                          preparedStatement.setString(5, bestPracticeChecksid.getCategory());
                          preparedStatement.setTimestamp(6, getCurrentTimeStamp());
                          preparedStatement.setString(7, readDateofResults());
                          preparedStatement.addBatch();

        }

        preparedStatement.executeBatch();

        dbConnection.commit();

错误日志如下：

 Exception in thread "main" java.lang.NullPointerException
    at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:586)
    at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:524)
    at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:3551)
    at java.lang.String.valueOf(Unknown Source)
    at java.lang.StringBuffer.append(Unknown Source)
    at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
    at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
    at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
    at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
    at com.mysql.jdbc.Connection.registerStatement(Connection.java)
    at com.mysql.jdbc.Statement.<init>(Statement.java:197)
    at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:442)
    at com.mysql.jdbc.ServerPreparedStatement.asSql(ServerPreparedStatement.java:347)
    at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:524)
    at com.mysql.jdbc.ServerPreparedStatement.toString(ServerPreparedStatement.java:2327)
    at java.lang.String.valueOf(Unknown Source)
    at java.lang.StringBuffer.append(Unknown Source)
    at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
    at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
    at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
    at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
    at com.mysql.jdbc.Connection.registerStatement(Connection.java)
    at com.mysql.jdbc.Statement.<init>(Statement.java:197)
    at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:423)
    at com.mysql.jdbc.ServerPreparedStatement.<init>(ServerPreparedStatement.java:280)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4363)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4301)
    at com.tutorialspoint.JDBCBatchUpdateExample.batchInsertRecordsIntoTable(JDBCBatchUpdateExample.java:49)
    at com.tutorialspoint.JDBCBatchUpdateExample.main(JDBCBatchUpdateExample.java:29)

Answer 1

我已经通过将mysql连接器jar升级到最新版本解决了上述问题。看起来像tracer.aj掩盖了进程，因此显示了空指针异常。我从来没有怀疑过我的代码:) 信用：Null Pointer Exception for prepared statement Sql Connection in java

插入从JSON检索的多个记录，这些记录在JDBC中使用POJO进行解析

1 个答案: