Qt进行CSV文件操作

Qt操作csv文件

csv文件简述
逗号分隔值（Comma-Separated Values，CSV，有时也称为字符分隔值，因为分隔字符也可以不是逗号），其文件以纯文本形式存储表格数据（数字和文本）。纯文本意味着该文件是一个字符序列，不含必须像二进制数字那样被解读的数据。CSV文件由任意数目的记录组成，记录间以某种换行符分隔；每条记录由字段组成，字段间的分隔符是其它字符或字符串，最常见的是逗号或制表符。

示例代码

头文件

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
namespace Ui {

class Widget;

}
class Widget : public QWidget

{

Q_OBJECT
public:

explicit Widget(QWidget *parent = 0);

~Widget();
private slots:

void onBtn();

void onOpenBtn();
private:

Ui::Widget *ui;

};
#endif // WIDGET_H
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信号绑定

connect(ui->pushButton, &QPushButton::clicked, this, &Widget::onBtn);
connect(ui->pushButton_open, &QPushButton::clicked, this, &Widget::onOpenBtn);
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此信号与槽函数的关联在构造函数中实现即可。

槽函数：onBtn

QString csvFileName = QFileDialog::getSaveFileName(this, QStringLiteral("保存文件设置"), ".", "csv files(*.csv)");
    QFile file(csvFileName);
    if(!file.exists())
    {
        file.open(QIODevice::WriteOnly);
        QTextStream csvOutPut(&file);
        QString str ="姓名,班级,年龄\n";
        csvOutPut << str.toUtf8();
        file.close();
    }
<span class="token keyword">if</span><span class="token punctuation">(</span><span class="token operator">!</span>file<span class="token punctuation">.</span><span class="token function">open</span><span class="token punctuation">(</span>QIODevice<span class="token operator">::</span>WriteOnly <span class="token operator">|</span> QIODevice<span class="token operator">::</span>Append<span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token punctuation">{<!-- --></span>
    <span class="token function">qDebug</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&lt;&lt;</span> <span class="token string">"0000000000000000000000"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">else</span>
<span class="token punctuation">{<!-- --></span>
    QTextStream <span class="token function">csvOutPut</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>file<span class="token punctuation">)</span><span class="token punctuation">;</span>
    QString str1 <span class="token operator">=</span> <span class="token string">"张三,3年级1班,28\n"</span><span class="token punctuation">;</span>
    QString str2 <span class="token operator">=</span> <span class="token string">"李四,3年级2班,36\n"</span><span class="token punctuation">;</span>
    QString str3 <span class="token operator">=</span> <span class="token string">"王五,3年级2班,36\n"</span><span class="token punctuation">;</span>

    csvOutPut <span class="token operator">&lt;&lt;</span> str1<span class="token punctuation">.</span><span class="token function">toUtf8</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    csvOutPut <span class="token operator">&lt;&lt;</span> str2<span class="token punctuation">.</span><span class="token function">toUtf8</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    csvOutPut <span class="token operator">&lt;&lt;</span> str3<span class="token punctuation">.</span><span class="token function">toUtf8</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    file<span class="token punctuation">.</span><span class="token function">flush</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    file<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

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运行结果：
在这里插入图片描述

槽函数：onOpenBtn

QString fileName = QFileDialog::getOpenFileName(this,QStringLiteral("打开文件"),".",tr("csv files(*.csv)"));
    if(fileName == "")
    {
        return;
    }
QFile <span class="token function">file</span><span class="token punctuation">(</span>fileName<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">if</span><span class="token punctuation">(</span><span class="token operator">!</span>file<span class="token punctuation">.</span><span class="token function">open</span><span class="token punctuation">(</span>QIODevice<span class="token operator">::</span>ReadOnly<span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token punctuation">{<!-- --></span>
    <span class="token function">qDebug</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">&lt;&lt;</span><span class="token function">QStringLiteral</span><span class="token punctuation">(</span><span class="token string">"请正确选择csv文件"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">else</span>
<span class="token punctuation">{<!-- --></span>
    QTextStream <span class="token operator">*</span> read <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token function">QTextStream</span><span class="token punctuation">(</span><span class="token operator">&amp;</span>file<span class="token punctuation">)</span><span class="token punctuation">;</span>
    QStringList Data <span class="token operator">=</span> read<span class="token operator">-</span><span class="token operator">&gt;</span><span class="token function">readAll</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">split</span><span class="token punctuation">(</span><span class="token string">"\n"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>            <span class="token comment">//每行以\n区分</span>
    <span class="token keyword">for</span><span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span> <span class="token punctuation">;</span> i <span class="token operator">&lt;</span> Data<span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-</span> <span class="token number">1</span> <span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span>               <span class="token comment">//去掉最后一行空白行</span>
    <span class="token punctuation">{<!-- --></span>
         QStringList strLine <span class="token operator">=</span> Data<span class="token punctuation">.</span><span class="token function">at</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">split</span><span class="token punctuation">(</span><span class="token string">","</span><span class="token punctuation">)</span><span class="token punctuation">;</span>         <span class="token comment">//一行中的单元格以，区分</span>
         <span class="token function">qDebug</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">&lt;&lt;</span> strLine<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

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运行结果：
在这里插入图片描述

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Qt操作csv文件

示例代码

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