DbUtils使用例子

// Create a ResultSetHandler implementation to convert the
// first row into an Object[].
ResultSetHandler<Object[]> h = new ResultSetHandler<Object[]>() {
    public Object[] handle(ResultSet rs) throws SQLException {
        if (!rs.next()) {
            return null;
        }
    
        ResultSetMetaData meta = rs.getMetaData();
        int cols = meta.getColumnCount();
        Object[] result = new Object[cols];

        for (int i = 0; i < cols; i++) {
            result[i] = rs.getObject(i + 1);
        }

        return result;
    }
};

// Create a QueryRunner that will use connections from
// the given DataSource
QueryRunner run = new QueryRunner(dataSource);

// Execute the query and get the results back from the handler
Object[] result = run.query(
    "SELECT * FROM Person WHERE name=?", h, "John Doe");

ResultSetHandler<Object[]> h = ... // Define a handler the same as above example

// No DataSource so we must handle Connections manually
QueryRunner run = new QueryRunner();

Connection conn = ... // open a connection
try{
    Object[] result = run.query(
        conn, "SELECT * FROM Person WHERE name=?", h, "John Doe");
        // do something with the result
        
} finally {
    // Use this helper method so we don‘t have to check for null
    DbUtils.close(conn);  
}

QueryRunner run = new QueryRunner( dataSource );
try
{
    // Execute the SQL update statement and return the number of
    // inserts that were made
    int inserts = run.update( "INSERT INTO Person (name,height) VALUES (?,?)",
                              "John Doe", 1.82 );
    // The line before uses varargs and autoboxing to simplify the code

    // Now it‘s time to rise to the occation...
    int updates = run.update( "UPDATE Person SET height=? WHERE name=?",
                              2.05, "John Doe" );
    // So does the line above
}
catch(SQLException sqle) {
    // Handle it
}

ExecutorCompletionService<Integer> executor =
    new ExecutorCompletionService<Integer>( Executors.newCachedThreadPool() );
AsyncQueryRunner asyncRun = new AsyncQueryRunner( dataSource );

try
{
    // Create a Callable for the update call
    Callable<Integer> callable = asyncRun.update( "UPDATE Person SET height=? WHERE name=?",
                                                  2.05, "John Doe" );
    // Submit the Callable to the executor
    executor.submit( callable );
} catch(SQLException sqle) {
    // Handle it
}

// Sometime later (or in another thread)
try
{
   // Get the result of the update
   Integer updates = executor.take().get();
} catch(InterruptedException ie) {
    // Handle it
}

QueryRunner run = new QueryRunner(dataSource);

// Use the BeanHandler implementation to convert the first
// ResultSet row into a Person JavaBean.
ResultSetHandler<Person> h = new BeanHandler<Person>(Person.class);

// Execute the SQL statement with one replacement parameter and
// return the results in a new Person object generated by the BeanHandler.
Person p = run.query(
    "SELECT * FROM Person WHERE name=?", h, "John Doe"); 

QueryRunner run = new QueryRunner(dataSource);

// Use the BeanListHandler implementation to convert all
// ResultSet rows into a List of Person JavaBeans.
ResultSetHandler<List<Person>> h = new BeanListHandler<Person>(Person.class);

// Execute the SQL statement and return the results in a List of
// Person objects generated by the BeanListHandler.
List<Person> persons = run.query("SELECT * FROM Person", h);