以JDBC的回調函數操作為例：

1、定義一個回調函數接口：用于收集查詢結果并轉換成實體

import java.sql.ResultSet; import java.sql.SQLException; import java.util.List;public interface ResultSetCall<T> {public List<T> getList(ResultSet resultSet) throws SQLException;}2、定義一個參數回調接口和默認實現類，用于填充參數

import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.SQLException;public interface PrepareStatementCall {public PreparedStatement getPrepareStatement(Connection con, String sql, Object[] params) throws SQLException; }
import java.sql.CallableStatement; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.SQLException;public class DefaultPrepareStatementCall implements PrepareStatementCall{@Overridepublic PreparedStatement getPrepareStatement(Connection con, String sql, Object[] params) throws SQLException {CallableStatement pre = con.prepareCall(sql);for(int i=0;i<params.length;i++){pre.setObject(i+1, params[i]);}return pre;}}
3、調用Dao：

public abstract class BaseDao<T> {protected DataSource dataSource;private PrepareStatementCall call = new DefaultPrepareStatementCall();public List<T> queryList(String sql, Object[] params, PrepareStatementCall call, ResultSetCall<T> resultSetCall){Connection con = null;PreparedStatement pre = null;ResultSet set = null;List<T> rs = null;try {con = dataSource.getConnection();pre = call.getPrepareStatement(con, sql, params);set = pre.executeQuery();rs = resultSetCall.getList(set);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{this.colseResultSet(set);this.colsePreparedStatement(pre);this.colseConnection(con);}return rs;}4、調用示例：

List<CompleteTask> rs = super.queryList(COMPLETE_NEW_SQL, new Object[]{waybillStatus, eachFetchDataNum}, new ResultSetCall<CompleteTask>(){@Overridepublic List<CompleteTask> getList(ResultSet set) throws SQLException {List<CompleteTask> rs = new ArrayList<CompleteTask>();while(set.next()){CompleteTask task = new CompleteTask();task.setTaskId(<span style="font-family: Arial, Helvetica, sans-serif;">set.getInt("taskId")</span><span style="font-family: Arial, Helvetica, sans-serif;">);</span>task.setTaskType(<span style="font-family: Arial, Helvetica, sans-serif;">set.getInt("taskType")</span><span style="font-family: Arial, Helvetica, sans-serif;">);</span> <span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>} <span style="white-space:pre"> </span>return rs; <span style="white-space:pre"> </span>} <span style="white-space:pre"> </span>} </span>

總結

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