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應(yīng)用Java泛型和反射導(dǎo)出CSV文件的方法

2019-11-26 15:20:11
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本文實(shí)例講述了應(yīng)用Java泛型和反射導(dǎo)出CSV文件的方法。分享給大家供大家參考。具體如下:

項(xiàng)目中有需求要把數(shù)據(jù)導(dǎo)出為CSV文件,因?yàn)椴煌念愑胁煌膶傩裕瑸榱舜a簡單,應(yīng)用Java的泛型和反射,寫了一個(gè)函數(shù),完成導(dǎo)出功能。

復(fù)制代碼 代碼如下:
public <T> void saveFile(List<T> list, String outFile) throws IOException {
        if (list == null || list.isEmpty()) {
            return;
        }
        if (StringUtils.isEmpty(outFile)) {
            throw new IllegalArgumentException("outfile is null");
        }
        boolean isFirst = true;
        BufferedWriter out = null;
        try {
            out = new BufferedWriter(new FileWriter(outFile));
            for (T t : list) {
                StringBuilder sb1 = new StringBuilder();
                StringBuilder sb2 = new StringBuilder();
                Class clazz = (Class) t.getClass();
                Field[] fs = clazz.getDeclaredFields();
                for (int i = 0; i < fs.length; i++) {
                    Field f = fs[i];
                    f.setAccessible(true);
                    try {
                        if (isFirst) {
                            sb1.append(f.getName());
                            sb1.append(",");
                        }
                        Object val = f.get(t);
                        if (val == null) {
                            sb2.append("");
                        } else {
                            sb2.append(val.toString());
                        }
                        sb2.append(",");
                    } catch (IllegalArgumentException | IllegalAccessException e) {
                        e.printStackTrace();
                    }
                }
                if (isFirst) {
                    out.write(sb1.toString());
                    isFirst = false;
                    out.newLine();
                }
                out.write(sb2.toString());
                out.newLine();
            }
        } catch (IOException e1) {
            throw e1;
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
            } catch (IOException e2) {
                throw e2;
            }
        }
}

希望本文所述對(duì)大家的Java程序設(shè)計(jì)有所幫助。

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