Spring周边：Template Method 模式

package webj2ee.tmplateMethod;

public abstract class AbstractClass {

    // 基本操作
    protected abstract void primitiveOperation1();

    // 基本操作
    protected abstract void primitiveOperation2();

    // 模板方法
    public void templateMethod(){
        primitiveOperation1();
        primitiveOperation2();
    }
}

package webj2ee.tmplateMethod;

public class ConcreteClass extends AbstractClass{
    @Override
    protected void primitiveOperation1() {
        // 业务逻辑处理
    }

    @Override
    protected void primitiveOperation2() {
        // 业务逻辑处理
    }
}

package webj2ee.tmplateMethod;

public class Client {
    public static void main(String[] args) {
        AbstractClass clz = new ConcreteClass();
        
        // 调用模板方法
        clz.templateMethod();
    }
}

  @Override
  @Nullable
  public <T> T execute(StatementCallback<T> action) throws DataAccessException {
    Assert.notNull(action, "Callback object must not be null");

    Connection con = DataSourceUtils.getConnection(obtainDataSource());
    Statement stmt = null;
    try {
      stmt = con.createStatement();
      applyStatementSettings(stmt);
      T result = action.doInStatement(stmt);
      handleWarnings(stmt);
      return result;
    }
    catch (SQLException ex) {
      // Release Connection early, to avoid potential connection pool deadlock
      // in the case when the exception translator hasn't been initialized yet.
      String sql = getSql(action);
      JdbcUtils.closeStatement(stmt);
      stmt = null;
      DataSourceUtils.releaseConnection(con, getDataSource());
      con = null;
      throw translateException("StatementCallback", sql, ex);
    }
    finally {
      JdbcUtils.closeStatement(stmt);
      DataSourceUtils.releaseConnection(con, getDataSource());
    }
  }
  
  @Override
  @Nullable
  public <T> T query(final String sql, final ResultSetExtractor<T> rse) throws DataAccessException {
    Assert.notNull(sql, "SQL must not be null");
    Assert.notNull(rse, "ResultSetExtractor must not be null");
    if (logger.isDebugEnabled()) {
      logger.debug("Executing SQL query [" + sql + "]");
    }

    /**
     * Callback to execute the query.
     */
    class QueryStatementCallback implements StatementCallback<T>, SqlProvider {
      @Override
      @Nullable
      public T doInStatement(Statement stmt) throws SQLException {
        ResultSet rs = null;
        try {
          rs = stmt.executeQuery(sql);
          return rse.extractData(rs);
        }
        finally {
          JdbcUtils.closeResultSet(rs);
        }
      }
      @Override
      public String getSql() {
        return sql;
      }
    }

    return execute(new QueryStatementCallback());
  }