Java 如何重构这个开关盒
我试图从excel中读取数据,从每一列中提取数据并将其存储在另一个变量中。每个大小写表示列。使用fbDataField,我将行数据添加到列表名fbList中。这个代码可以被重构,使它看起来是一个干净的代码吗Java 如何重构这个开关盒,java,refactoring,Java,Refactoring,我试图从excel中读取数据,从每一列中提取数据并将其存储在另一个变量中。每个大小写表示列。使用fbDataField,我将行数据添加到列表名fbList中。这个代码可以被重构,使它看起来是一个干净的代码吗 for(int i=0;i< workbook.getNumberOfSheets(); i++){ Sheet sheet = workbook.getSheetAt(i); Iterator<Row> rowIterator = sheet.iter
for(int i=0;i< workbook.getNumberOfSheets(); i++){
Sheet sheet = workbook.getSheetAt(i);
Iterator<Row> rowIterator = sheet.iterator();
while(rowIterator.hasNext()){
FacebookFields fbDataField= new FacebookFields();
Row row = rowIterator.next();
if(row.getRowNum()== 0 )
{
continue;
}
Iterator<Cell> cellIterator = row.cellIterator();
while(cellIterator.hasNext()){
Cell cell= cellIterator.next();
switch(cell.getColumnIndex()){
case 0: fbDataField.setName(cell.getStringCellValue());
break;
case 1: fbDataField.setId(cell.getStringCellValue());
break;
case 2: fbDataField.setDate(cell.getStringCellValue());
break;
case 3: fbDataField.setMessage(cell.getStringCellValue());
break;
case 4: fbDataField.setType(cell.getStringCellValue());
break;
case 5: fbDataField.setPage(cell.getStringCellValue());
break;
case 6: fbDataField.setLikeCount(String.valueOf(cell.getNumericCellValue()));
break;
case 7: fbDataField.setCommentCount(String.valueOf(cell.getNumericCellValue()));
break;
case 8: fbDataField.setShareCount(String.valueOf(cell.getNumericCellValue()));
break;
}
}
fbList.add(fbDataField);
}
}
for(int i=0;i
POI的文档说明它有迭代器()
别名以启用foreach循环:
for (Sheet sheet : workbook) {
for (Row row : sheet) {
if (row.getRowNum() == 0) {
continue;
}
FacebookFields record = new FacebookFields();
for (Cell cell : row) {
switch (cell.getColumnIndex()) {
case 0: record.setName (cell.getStringCellValue()); break;
case 1: record.setId (cell.getStringCellValue()); break;
case 2: record.setDate (cell.getStringCellValue()); break;
case 3: record.setMessage (cell.getStringCellValue()); break;
case 4: record.setType (cell.getStringCellValue()); break;
case 5: record.setPage (cell.getStringCellValue()); break;
case 6: record.setLikeCount (String.valueOf(cell.getNumericCellValue())); break;
case 7: record.setCommentCount(String.valueOf(cell.getNumericCellValue())); break;
case 8: record.setShareCount (String.valueOf(cell.getNumericCellValue())); break;
}
}
fbList.add(record);
}
}
注:
<> Li >我考虑将数值字段的类型改为不是<代码>字符串< /代码>
for(工作表:工作簿){
阅读表(表,fbList);
}
专用静态无效读表(最终表、最终列表){
用于(行:页)
if(row.getRowNum()>0)
fbList.add(readRow(row));
}
私有静态FacebookFields readRow(最后一行){
FacebookFields记录=新的FacebookFields();
用于(单元格:行){
开关(cell.getColumnIndex()){
案例0:record.setName(cell.getStringCellValue());break;
案例1:record.setId(cell.getStringCellValue());break;
案例2:record.setDate(cell.getStringCellValue());break;
案例3:record.setMessage(cell.getStringCellValue());break;
案例4:record.setType(cell.getStringCellValue());break;
案例5:record.setPage(cell.getStringCellValue());break;
案例6:record.setLikeCount(cell.getNumericCellValue());break;
案例7:record.setCommentCount(cell.getNumericCellValue());break;
案例8:record.setShareCount(cell.getNumericCellValue());break;
}
}
返回记录;
}
例如
²我会使用
枚举
作为复制工厂
enum CellToFb {
Name {
@Override
void copy(FacebookFields fb, Cell cell) {
fb.setName(cell.getStringCellValue());
}
},
Id {
@Override
void copy(FacebookFields fb, Cell cell) {
fb.setId(cell.getStringCellValue());
}
};
// Every enum must be able to copy one cell to the correct FB field.
public abstract void copy(FacebookFields fb, Cell cell);
}
public void test() {
// Get all copiers - one for each column.
CellToFb[] copiers = CellToFb.values();
while (cellIterator.hasNext()) {
Cell cell = cellIterator.next();
// Call the correct copier.
copiers[cell.getColumnIndex()].copy(fbDataField, cell);
}
}
每个枚举都知道如何复制特定列。只需确保枚举与列匹配即可。您的复制代码变得非常简单
这种技术很好地移植到Java8Lambdas
// Couple of simple demo classes.
class From {
String id;
String name;
@Override
public String toString() {
return "{" + id + "," + name + "}";
}
}
class To {
String identifier;
String value;
@Override
public String toString() {
return "{" + identifier + "," + value + "}";
}
}
enum FromToTo implements BiConsumer<To, From> {
// Each field defines it's own copying lambda.
Id((to, from) -> to.identifier = from.id),
Value((to, from) -> to.value = from.name);
// The copying lambda.
private final BiConsumer<To, From> copy;
private FromToTo(BiConsumer<To, From> copy) {
this.copy = copy;
}
@Override
public void accept(To to, From from) {
// Delegate to the copying lambda.
copy.accept(to, from);
}
// Take s static copy to avoid duplicating.
private static final FromToTo[] copiers = FromToTo.values();
public static void copy(To to, From from) {
// Useful function to copy fields from -> to
Arrays.stream(copiers)
.forEach(ftt -> ftt.accept(to, from));
}
}
public void test() {
From f = new From();
f.id = "id";
f.name = "name";
To t = new To();
FromToTo.copy(t, f);
System.out.println(f + " -> " + t);
}
//两个简单的演示类。
来自{
字符串id;
字符串名;
@凌驾
公共字符串toString(){
返回“{id+”,“+name+”}”;
}
}
归类于{
字符串标识符;
字符串值;
@凌驾
公共字符串toString(){
返回“{”+标识符+”,“+值+”}”;
}
}
枚举FromToTo实现双消费{
//每个字段定义自己的复制lambda。
Id((to,from)->to.identifier=from.Id),
值((to,from)->to.Value=from.name);
//复制lambda。
私人最终双消费者副本;
私人FromToTo(双消费者副本){
this.copy=复制;
}
@凌驾
公共无效接受(收件人、发件人){
//委托给复制lambda。
复制。接受(到,从);
}
//采取静态拷贝,以避免重复。
私有静态最终FromToToTo[]复印机=FromToToTo.values();
公共静态无效副本(收件人、发件人){
//将字段从->复制到的有用功能
阵列.流(复印机)
.forEach(ftt->ftt.accept(to,from));
}
}
公开无效测试(){
From f=新的From();
f、 id=“id”;
f、 name=“name”;
To t=新到();
FromToTo.副本(t,f);
系统输出打印LN(f+“->”+t);
}
如果在问题中添加适当的语言标记,您可能会得到更好的回答。我不能决定它是C++还是java(用C语言另一种可能)。本例中的代码布局很糟糕,但可能有更好的方法来组织代码。只需创建一个新类来处理开关
状态,重构就完成了。重构不是重新发明轮子,而是将代码分割成更小的逻辑部分。基本上,任何可以做某事并可以用动词描述的代码都应该是class/method。@法律为什么要创建一个新类?这个类已经存在,它被称为List
@elyse,我认为这是关于代码设计中的偏好。为了便于阅读,我喜欢将我的类保持在屏幕的最大长度,并按功能将它们分开。我如何摆脱开关盒?为什么?你不会,除非你做了一个更复杂的设计。除非你一直在读不同的表格布局,否则我不会time@OldCurmudgeon刚刚发布了一个妙招,我想为这种情况推荐:)这是一个我从未见过的非常好的习惯用法。@sehe-它也能适应变化!添加
// Couple of simple demo classes.
class From {
String id;
String name;
@Override
public String toString() {
return "{" + id + "," + name + "}";
}
}
class To {
String identifier;
String value;
@Override
public String toString() {
return "{" + identifier + "," + value + "}";
}
}
enum FromToTo implements BiConsumer<To, From> {
// Each field defines it's own copying lambda.
Id((to, from) -> to.identifier = from.id),
Value((to, from) -> to.value = from.name);
// The copying lambda.
private final BiConsumer<To, From> copy;
private FromToTo(BiConsumer<To, From> copy) {
this.copy = copy;
}
@Override
public void accept(To to, From from) {
// Delegate to the copying lambda.
copy.accept(to, from);
}
// Take s static copy to avoid duplicating.
private static final FromToTo[] copiers = FromToTo.values();
public static void copy(To to, From from) {
// Useful function to copy fields from -> to
Arrays.stream(copiers)
.forEach(ftt -> ftt.accept(to, from));
}
}
public void test() {
From f = new From();
f.id = "id";
f.name = "name";
To t = new To();
FromToTo.copy(t, f);
System.out.println(f + " -> " + t);
}