问题
I'm learning JDBC at the moment and I already know the difference between PreparedStatement and Statement. It is that PreparedStatement is precompiled and allows you to set parameters, but I was asked a question on a job interview about difference between PreparedStatement batch and Statement batch?
回答1:
The difference between batch execution of a Statement and PreparedStatement, is that a Statement batch can contain different statements (as long as they are statements that do not produce a result set), for example a single batch can contain all kinds of inserts into various tables, deletes, updates, and - not in all JDBC driver implementations AFAIK - even DDL statements.
On the other hand, a PreparedStatement batch execution concerns a single statement, and the batch contains the multiple sets of parameter values to execute for that statement. That is, each batch entry defines the values to use for the parameters of the prepared statement.
In short:
Statement: batch can contain a lot of different statementsPreparedStatement: single statement, multiple sets of parameter values
回答2:
Statement is used for executing a static SQL statement and returning the results it produces.
In PreparedStatement, a SQL statement is precompiled and stored in a PreparedStatement object. This object can then be used to efficiently execute this statement multiple times. As sql statement is already compiled you will saved some time.
PreparedStatement interface extends Statement interface.
public interface PreparedStatement extends Statement
Batch Processing:
Batch Processing means the batch will be done in "all at once". In batch you can execute multiple statement in single transaction instead of executing them one by one. It will also improve performance because you are making one round trip to database server to insert multiple records instead of multiple trips.
executeBatch() API is a part of Statement interface which submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts.
You create multiple statement/preparedstatment and add it to a batch. To execute it instead of
statement.execute(); //executes single statement/preparedstatement
you call
statement.addBatch(); //to add statement to batch
statement.executeBatch(); //executes batch of statement/preparedstatement
As SQL is pre-compiled and cannot be changed in preparedstatement, batch will same SQL multiple times whereas in case of Statement, you can add different SQLs to batch.
来源：https://stackoverflow.com/questions/42397522/difference-between-preparedstatement-batch-and-statement-batch