0000001_java学习之路

来源：互联网发布：用友软件怎么用编辑：程序博客网时间：2024/05/21 06:46

今天学了俩小东西
<1>根据数据库读取的数据动态改变字符串数组的内容
e.g.

    private String[] titles;    private String[] payTypes;    //for循环之后titles内容变成titles = {"学生姓名", "身份证号", "学号","书费","空调费"};    titles = new String[] { "学生姓名", "身份证号", "学号" };    for (int i=0;i<this.getPayTypes().length;i++) {            this.titles = this.insert(titles, this.getPayTypes()[i]);    }    private String[] insert(String[] arr, String str)    {            int size = arr.length;                           String[] tmp = new String[size + 1];                     System.arraycopy(arr, 0, tmp, 0, size);                   tmp[size] = str;                         return tmp;        //动态得到一个字符串数组    public String[] getPayTypes() {        //假设这个初始化之后内容是payTypes = {"书费","空调费"};        payTypes = students.get(0).getPayTypes();        return payTypes;    }

<2>将一个List 转换成 String[]
e.g.

    List<String> list = new ArrayList<String>();    String[] str = new String[list.size()];    list.toArray(str);

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