定義接口 規范文件操作類型

import java.util.List;/*** 控制普通文件讀取操作的類* 一般來講是換行讀取、字符流* @param <T> 待存取的類型*/ public interface IFileOperation<T> {/*** 增* @param object*/void add(T object);/*** 刪* @param object*/void delete(T object);/*** 查* @return*/List<T> getAll();/*** 改* @param object*/void update(T object);}

文本類型數據文件內容：

ID#Code#Name#Classification#Type 1#XXGNK#心血管內科#內科#臨床 2#SJNK#神經內科#內科#臨床 3#PTNK#普通內科#內科#臨床 4#XHNK#消化內科#內科#臨床 5#HXNK#呼吸內科#內科#臨床 6#NFMK#內分泌科#內科#臨床 7#SBNK#腎病內科#內科#臨床

讀寫分析

插入操作，為簡便起見，建議插在末尾。
刪除操作，不建議在遍歷中刪除，因為迭代器遍歷（增強for循環實質上是迭代器）中并發修改會fail-fast，拋出并發修改異常。
修改操作，在循環的時候也是，貌似寫不進去的。
查詢操作，很簡單啦，查就完事。

建議全取出來再處理，畢竟IO真的慢，一直是一邊IO一邊操作也不太現實吧（這可不是數據庫，數據庫有些功能直接在SQL里指定了）。

實現類Mapper

肯定是單例模式啦。
實現上面的接口，給一個類型，實現對應的增刪改查方法。
另外，處理好讀寫格式很重要，其中我用的是多個“+”連接字符串，其實這么多的連接就完全可以用StringBuilder了。

public class DepartmentMapper implements IFileOperation<Department> {private static DepartmentMapper mapper;private DepartmentMapper() {}/*** 獲取單例* @return*/public static DepartmentMapper getInstance() {if (mapper == null) {mapper = new DepartmentMapper();}return mapper;}/*** 根據傳入對象插入部門*/@Overridepublic void add(Department object) {if (object != null) { List<Department> departmentList = getAll();for (Department department : departmentList) {if (department.getId().equals(object.getId())) {return;}}departmentList.add(object);writeDepartment(departmentList);} }/*** 根據傳入對象刪除部門*/@Overridepublic void delete(Department object) {List<Department> departmentList = getAll();Department deleteObj = null;for (Department department : departmentList) {if (department.getId().equals(object.getId())) {deleteObj = department;break;}}if (deleteObj != null) {departmentList.remove(deleteObj);}writeDepartment(departmentList);}/*** 獲取所有部門*/@Overridepublic List<Department> getAll() {List<Department> departmentList = new ArrayList<>();try (Scanner scanner = new Scanner(new FileReader(DEPARTMENT_FILENAME))) {scanner.nextLine();while (scanner.hasNextLine()) {String line = scanner.nextLine();departmentList.add(generateDepartment(line));}} catch (IOException ioe) {ioe.printStackTrace();}return departmentList;}/*** 更新一個部門信息*/@Overridepublic void update(Department object) {List<Department> departmentList = getAll();Department temp = null;for (Department department : departmentList) {if (department.getId().equals(object.getId())) {temp = department;break;}}temp= object;writeDepartment(departmentList);}/*** 完成修改后的寫入* @param departmentList*/private void writeDepartment(List<Department> departmentList) {try (BufferedWriter tempWriter = new BufferedWriter(new FileWriter(DEPARTMENT_FILENAME));BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(DEPARTMENT_FILENAME, true))) { tempWriter.write("");for (Department department : departmentList) {String line = department.getId() + SPLIT_CHARACTER + department.getCode() + SPLIT_CHARACTER+ department.getName() + SPLIT_CHARACTER + department.getClassification() + SPLIT_CHARACTER+ department.getType() + "\n";bufferedWriter.write(line);}} catch (IOException ioe) {ioe.printStackTrace();}}/*** 一個被封裝的方法，作用是把讀出來的一行拆分組合為一個Department對象* @param line* @return*/private Department generateDepartment(String line) {String[] strList = line.split(SPLIT_CHARACTER);int id = Integer.parseInt(strList[0]);String code = strList[1];String name = strList[2];String classification = strList[3];String type = strList[4];Department department = new Department(id, code, name, classification, type);return department;}/*** 依據科室名稱找到科室* @param name* @return*/public Department getElementByName(String name) {if (name == null) {return null;}List<Department> departmentList = getAll();for (Department department : departmentList) {if (name.equals(department.getName())) {return department;}}return null;}}

總結

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