如何在不使用POJO代码的情况下创建Java批处理插入 -DZone Java

21-01-15 banq

POJO样板代码通常用于Java程序的各种功能中:无论是使用comparator(comparable的接口)进行比较,还是诸如在“通用数据结构”中存储大量数据(例如列表,集合,地图等)之类的简单操作。但是,POJO管理起来非常困难,并且随着需求的不断变化,需要进行更多更改。但是,在这种情况下,不使用POJO代码。让我们看看下面的代码。

该程序通过执行以下步骤将ExcelSheet复制到SQL表。 

  1. 从提供位置的文件中获取网格数据。
  2. 从数据库获取连接。
  3. 该程序获取列数并分配该长度的数组。
  4. 拾取第一行并获取列名称,并将其存储在数组中。
  5. 检查网格中矩阵的一致性,指出不相等的行,否则返回true标志,指示行长度等于标题长度。
  6. 通过传递带有列标题作为表属性的DDL语句来创建表。
  7. 复制网格表中的所有行,并将它们传递给LinkedList。
  8. 将批处理大小初始化为100。在为每个获得的数组进行批处理插入循环期间,迭代其索引并将数组加载到批处理容器中。一旦循环达到100,则执行批处理。继续批量插入循环,直到LinkedList结束。 

public class DBFromExcel {
static FileInputStream excelFile = null;
static Workbook workbook = null;
static XSSFSheet datatypeSheet = null;
static Row row = null;
static PreparedStatement pr_stmt = null;
static Connection conn = null;
static String[] headers = null;
static String[] row_data = null;
static List<String[]> lst = null;
static String formattedDate = null;
public DBFromExcel() {
try {
excelFile = new FileInputStream(new File(<PATH TO EXCEL FILE>));
workbook = new XSSFWorkbook(excelFile);
Calendar cal = Calendar.getInstance();
Date date=cal.getTime();
DateFormat dateFormat = new SimpleDateFormat("YY");
formattedDate=dateFormat.format(date);
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/<table_name>",  "<db_user>", "<db_pass>");
} catch (IOException | ClassNotFoundException | SQLException e) { 
e.printStackTrace();

}
datatypeSheet = (XSSFSheet) workbook.getSheetAt(0);
row = ((org.apache.poi.ss.usermodel.Sheet) datatypeSheet).getRow(0);
StringBuilder strbld = new StringBuilder();
for (int i = 0; i < row.getLastCellNum(); i++) {
Cell cell = row.getCell(i);
if (cell != null) {
strbld.append(cell.getStringCellValue() + ",");
}
}
headers = strbld.toString().substring(0, strbld.toString().length() - 1).split(",");
if (check_matrix_consistency(datatypeSheet) == true)
{
try {
pr_stmt = conn.prepareStatement(create_table(headers));
pr_stmt.execute();
} catch (SQLException e1) { 
e1.printStackTrace();
}
try {
System.out.println("INSERT INTO T_"+formattedDate+" (" + strbld.toString().substring(0, strbld.toString().length() - 1)+ ") VALUES ("+generate_containers(headers)+")");
pr_stmt = conn.prepareStatement("INSERT INTO T_"+formattedDate+" (" + strbld.toString().substring(0, strbld.toString().length() - 1)+ ") VALUES ("+generate_containers(headers)+");");
} catch (SQLException e) {
e.printStackTrace();
}
try {
getRows(datatypeSheet);
} catch (SQLException e) {
e.printStackTrace();
}
try {
insert_rows();
} catch (SQLException e) { 
e.printStackTrace();
}
} else {
System.out.println("Matrix config error");
}
}
private String create_table(String[] headers) {
StringBuffer strbuff = new StringBuffer();
strbuff.append("CREATE TABLE T_"+formattedDate+" ("+"\n");
int counter=0;
while(counter<headers.length)
{
strbuff.append(headers[counter]+" VARCHAR(50) NULL DEFAULT NULL,"+"\n");
counter++;
}
System.out.println(strbuff.substring(0,strbuff.toString().length()-2)+")COLLATE='utf8_general_ci' ENGINE=MyISAM;");
return strbuff.substring(0,strbuff.toString().length()-2)+")COLLATE='utf8_general_ci' ENGINE=MyISAM;";
}
private String generate_containers(String[] headers) {
StringBuffer strbuff = new StringBuffer();
int counter = 0;
while (counter <= headers.length-1) {
strbuff.append("?,");
counter++;
}
return strbuff.substring(0, strbuff.toString().length() - 1);
}
private static boolean check_matrix_consistency(XSSFSheet sheet) {
boolean flag = true;
for (int i = 0; i < sheet.getLastRowNum(); i++) {
Row row = sheet.getRow(i);
if (headers.length != sheet.getRow(1).getLastCellNum()) {
System.out.println("Error at row number" + i);
flag = false;
break;
} else {
if (headers.length != row.getLastCellNum()) {
System.out.println("Error at row number" + i);
flag = false;
continue;
}
}
}
return flag;
}

private static void insert_rows() throws SQLException {
int batch = 100;
for (int i = 0; i < lst.size(); i++) {
System.out.println(i);
String[] obtained_row = lst.get(i);
int counter = 0;
for (int j = 0; j < obtained_row.length; j++) {
counter++;
pr_stmt.setString(counter, obtained_row[j]);
}
pr_stmt.addBatch();
if (i % batch == 0 || i < lst.size()) {
pr_stmt.executeBatch();
}
}
}
private static void getRows(XSSFSheet sheet) throws SQLException {
lst = new LinkedList<String[]>();
for (int i = 1; i < sheet.getLastRowNum() + 1; i++) {
Row row = sheet.getRow(i);
int counter = 0;
row_data = new String[headers.length];
for (int j = 0; j < row.getLastCellNum(); j++) {
Cell cell = row.getCell(j);
if (cell.getCellType() == CellType.STRING) {
setValue(counter, cell.getStringCellValue());
}
if (cell.getCellType() == CellType.NUMERIC) {
setValue(counter, cell.getNumericCellValue());
}
counter++;
}
lst.add(row_data);
}
}
public static void setValue(int position, String value) {
row_data[position] = value;
}
public static void setValue(int position, double value) {
row_data[position] = Double.toString(value);
}
public static void main(String args[]) {
new DBFromExcel();
}
}  

 

         

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