字符串操作
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StringBuild
效率最高,StringBuffer
最安全 -
需求要求按照某种格式拼接字符串时用到append方法链式拼接
StringBuilder sb=new StringBuilder(); sb.append(t.getName()). append(","+t.getChinese()). append(","+t.getMath()). append(","+t.getEnglish());
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最后把拼接好的字符串通过
toString
方法转换sb.toString
写入数据 -
例
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BufferedWriter bw =new BufferedWriter(new FileWriter("day02_IO\\a.txt")); for (Student t : ts) { // 格式:姓名,语文成绩,数学成绩,英语成绩举例:林青霞,98, 99, 100 // 拼接成绩使用StringBuild拼接 StringBuilder sb=new StringBuilder(); sb.append(t.getName()). append(","+t.getChinese()). append(","+t.getMath()). append(","+t.getEnglish()); bw.write(sb.toString());//最后记得toString传入参数 bw.newLine(); bw.flush(); }