【发布时间】：2011-12-19 15:16:51
【问题描述】：
我想将 SQL 查询的结果写入 csv 或 Excel 文件并将其保存在特定文件夹中。我有以下要求：
- 我想知道，这是否可以使用可用于任何 SQL 查询结果的 Java 程序来实现。
- 我也想知道，这是否可以用于不同的数据库（Oracle、MySQL、SQL Server 等）。
- 我打算将保存的文件附加到电子邮件中。是否可以直接将 SQL 查询结果导出到电子邮件？
【问题讨论】：
【发布时间】：2011-12-19 15:16:51
【问题描述】：
使用 openCSV API，您可以将数据导出为 csv 文件。
CSVWriter writer = new CSVWriter(new FileWriter("yourfile.csv"), '\t');
Boolean includeHeaders = true;
java.sql.ResultSet myResultSet = .... //your resultset logic here
writer.writeAll(myResultSet, includeHeaders);
writer.close();
【讨论】：
很难从任何工具中导出结果集数据。
例如：将结果集数据导出到 .csv 文件时，当数据包含 (,) 时无法正确导出
请参考下面的java代码：
它适用于任何查询输入和结果集中的所有类型的数据
package com.demo.export;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;
public class dataExportService {
public void getDefendants(Connection con , String db) throws Exception {
@SuppressWarnings("unused")
Workbook readWorkbook = WorkbookFactory.create(new FileInputStream(".xls file path(C:\\Users\\CEPL\\Desktop\\test.xls)") );
@SuppressWarnings("resource")
Workbook writeWorkbook = new HSSFWorkbook();
Sheet desSheet = writeWorkbook.createSheet("new sheet");
Statement stmt = null;
ResultSet rs = null;
try{
String query ="QUERY";
stmt = con.createStatement();
rs = stmt.executeQuery(query);
ResultSetMetaData rsmd = rs.getMetaData();
int columnsNumber = rsmd.getColumnCount();
Row desRow1 = desSheet.createRow(0);
for(int col=0 ;col < columnsNumber;col++) {
Cell newpath = desRow1.createCell(col);
newpath.setCellValue(rsmd.getColumnLabel(col+1));
}
while(rs.next()) {
System.out.println("Row number" + rs.getRow() );
Row desRow = desSheet.createRow(rs.getRow());
for(int col=0 ;col < columnsNumber;col++) {
Cell newpath = desRow.createCell(col);
newpath.setCellValue(rs.getString(col+1));
}
FileOutputStream fileOut = new FileOutputStream(".xls file path(C:\\Users\\CEPL\\Desktop\\test.xls)");
writeWorkbook.write(fileOut);
fileOut.close();
}
}
catch (SQLException e) {
System.out.println("Failed to get data from database");
}
}
}
【讨论】：
-
"ex: 在将结果集数据导出到 .csv 文件时，当数据包含 (,) 时无法正确导出"如果使用适当的工具，它将转义，将其括在引号中 "" ...
您可以使用 JDBC 在 java 中从 DB 中获取记录，然后使用 Apache POI 将数据导出到 CSV/Excel。
此外，您可以使用 java 的 desktop API 使用您的默认电子邮件客户端发送电子邮件。
【讨论】：
这是我的解决方案。插入主类的代码：
import java.io.*;
import java.sql.*;
import com.company.*;
/**
* Created by MAXNIGELNEGRO
*/
String[] filePath = new String[] {"C:\\Users\\Documents\\MyFile.csv"};
String[] driverDB = new String[] {"oracle.jdbc.driver.OracleDriver"};
String[] stringConnDB = new String[] {"jdbc:oracle:thin:@//127.0.0.1:1881/mydb"};
String[] userDB = new String[] {"pippo"};
String[] passDB = new String[] {"pluto"};
String[] charSep = new String[] {";"};
Boolean column= new Boolean (true);
String[] queryDB = new String[] {"select * FROM MYQUERY"};
try{
System.out.println("---------------File exist?------------" + filePath[0]);
File fileTemp = new File(filePath[0].toString());
if (fileTemp.exists()){
fileTemp.delete();
System.out.println("---------------DELETE FILE------------" + filePath[0] );
}
System.out.println("QUERY: ---->"+ queryDB[0].toString());
exportQueryToCsv exp = new exportQueryToCsv();
exp.exportQueryToCsv(filePath, driverDB, stringConnDB, userDB, passDB, queryDB, column, charSep);
if (fileTemp.exists()){
System.out.println("---File created---" + filePath[0]);
}
}
catch(Exception e){
e.printStackTrace();
}
核心类：
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
* Created by MAXNIGELNEGRO
*/
public class exportQueryToCsv {
public exportQueryToCsv(){}
public static void exportQueryToCsv (String[] filename, String[] driverDB, String[] connDB
, String[] userDB, String[] passDB, String[] queryDB, Boolean intestaFile
, String[] charSep) throws SQLException, IOException {
Statement stmt=null;
ResultSet rset=null;
Connection conn=null;
try { DBConn connessione = new DBConn();
conn=connessione.connect(driverDB[0],connDB[0],userDB[0],passDB[0]);
conn.setAutoCommit(false);
stmt = conn.createStatement();
rset = stmt.executeQuery(queryDB[0]);
ExportData2CSV csv = new ExportData2CSV();
csv.ExportData2CSV(rset,filename[0],intestaFile,charSep[0]);
csv.createFileCsv();
} catch (SQLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
if (stmt != null) {stmt.close();}
if (conn != null) {conn.close();}
if (rset != null) {rset.close();}
}
}
}
这是用于连接数据库的 DBConn 类：
import java.sql.*;
/**
* Created by MAXNIGELNEGRO
*/
public class DBConn {
public DBConn() {
}
public Connection connect(String driverDB, String db_connect_str, String db_userid, String db_password) {
Connection conn;
try {
Class.forName(driverDB).newInstance();
conn = DriverManager.getConnection(db_connect_str, db_userid, db_password);
} catch (Exception e) {
e.printStackTrace();
conn = null;
}
return conn;
}
}
这是从表中检索数据到结果集并写入 csv 文件的类：
package com.company;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
/**
* Created by MAXNIGELNEGRO
*/
public class ExportData2CSV {
public ResultSet rset;
public String filename;
public Boolean columnName;
public String charSep;
public void ExportData2CSV(ResultSet rset, String filename, Boolean columnName, String charSep) {
this.rset = rset;
this.filename = filename;
this.columnName = columnName;
this.charSep = charSep;
}
public void createFileCsv() throws SQLException, IOException {
FileWriter cname = null;
try {
// WRITE COLUMN NAME
ResultSetMetaData rsmd = rset.getMetaData();
cname = new FileWriter(filename);
if (columnName) {
for (int i = 1; i <= rsmd.getColumnCount(); i++) {
cname.append(rsmd.getColumnName(i));
cname.append(charSep);
cname.flush();
}
cname.append(System.getProperty("line.separator"));
}
// WRITE DATA
while (rset.next()) {
for (int i = 1; i <= rsmd.getColumnCount(); i++) {
if (rset.getObject(i) != null) {
String data = rset.getObject(i).toString().replaceAll(charSep, "");
cname.append(data);
cname.append(charSep);
} else {
String data = "null";
cname.append(data);
cname.append(charSep);
}
}
//new line entered after each row
cname.append(System.getProperty("line.separator"));
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (cname != null) {
cname.flush();
cname.close();
}
if (rset != null) {
rset.close();
}
}
}
}
【讨论】：
这是excel数据表
input excel file containing records 嗨，这是您需要 3 个文件的解决方案 1.输入线程 2.输出线程 3.数据结构 4.main 1.输入线程读取excel，输出线程写入sql输出 2.数据结构是保存和传输数据
(InputThread.java)
import java.io.*;
public class InputThread extends Thread{
String fp;
InputString is;
String tableName="emp";
String outFile;
InputThread(String FilePath,String nameOfTheTable,String outFileName){
fp=FilePath;
outFile=outFileName;
tableName=nameOfTheTable;
}
public void run(){
File file = new File(fp);
String line;
try{
BufferedReader br = new BufferedReader(new FileReader(file));
if( (line=br.readLine()) != null)
is = new InputString(line);
//transform(is);
InputString tmp = new InputString(createTable(line));
//tmp.next = is;
is = tmp;
//tmp = tmp.next;
for(; (line = br.readLine()) != null; ) {
tmp.next = new InputString(line);
tmp = tmp.next;
transform(tmp);
}
}catch(Exception e){ System.out.println("Error is :"+e); }
//traverse();
new OutputThread(is,outFile).start();
}
void transform(InputString x){
String[] arr = x.getLine().split(",");
String sql = "insert into "+tableName+" values(";
for(int i=0;i<arr.length;i++){
sql+="'"+arr[i]+"'";
if( (i+1) < arr.length) sql+=",";
}
sql+=");";
x.setLine(sql);
}
String createTable(String x){
String[] arr = x.split(",");
String sql = "create database vamsidb "+ "use vamsidb "+"create table "+tableName+"(";
for(int i=0;i<arr.length;i++){
sql+=arr[i]+" varchar(50)";
if( (i+1) < arr.length) sql+=",";
}
sql+=");";
return sql;
}
/*public void traverse(){
InputString tmp = is;
while(is != null){
System.out.println(is.getLine());
is=is.next;
}
}*/
}
（输出线程.java）
import java.io.*;
public class OutputThread extends Thread{
InputString is;
String outFile;
OutputThread(InputString linkedList,String outFileName){
is=linkedList;
outFile = outFileName;
}
public void run(){
try{
FileOutputStream fos = new FileOutputStream(outFile);
while(is != null){
fos.write(is.getLine().getBytes());
is=is.next;
}
fos.close();
}catch(Exception e){
System.out.println("Error is :"+e);
}
}
}
(Main.java)
public class Main{
public static void main(String[] args){
InputThread it = new InputThread("sasken.csv","emp","output.sql");
it.start();
}
}
(DataStructure.java)
//该类表示保存和转换输入的数据结构 //数据作为sql语句的链表
class InputString{
String line;
InputString next;
InputString(String x){
line = x;
}
String getLine(){
return line;
}
void setLine(String x){
line = x;
}
}
【讨论】：
是的！
您可以使用 jdbc 连接到不同的数据库类型，然后使用结果创建一个 Excel (Seen here)。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestAccessExcel {
public static Connection getConnection() throws Exception {
String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
String url = "jdbc:odbc:excelDB";
String username = "username";
String password = "pass";
Class.forName(driver);
return DriverManager.getConnection(url, username, password);
}
public static void main(String args[]) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
conn = getConnection();
stmt = conn.createStatement();
String excelQuery = "select * from [Sheet1$]";
rs = stmt.executeQuery(excelQuery);
while (rs.next()) {
System.out.println(rs.getString("BadgeNumber") + " " + rs.getString("FirstName") + " "
+ rs.getString("LastName"));
}
} catch (Exception e) {
System.err.println(e.getMessage());
} finally {
try {
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
【讨论】：
-
如果您在 Windows 环境中，这是一种非常巧妙的处理方式。它也相对“便携”，因为相同的想法适用于任何语言。 Apache 替代方案也不错。
-
该示例展示了如何从 Excel 电子表格中读取数据，而不是如何创建。
最简单的解决方案。
主要方法
private List<String> resultSetArray=new ArrayList<>();
private String username =""; // Enter DB Username
private String password = ""; // Enter DB password
private String url = ""; // Enter DB URL
Connection connection=DriverManager.getConnection(url,user,pwd);
public static void main(String args[]) throws Exception{
fetchDataFromDatabase("SQL queries", connection);
printToCsv(resultArray);
}
fetchDataFromDatabase
下面的代码计算一个表的列数，并存储在一个结果数组中。
private void fetchDataFromDatabase(String selectQuery,Connection connection) throws Exception{
try {
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(selectQuery);
int numCols = rs.getMetaData().getColumnCount();
while(rs.next()) {
StringBuilder sb = new StringBuilder();
for (int i = 1; i <= numCols; i++) {
sb.append(String.format(String.valueOf(rs.getString(i))) + " ");
}
resultSetArray.add(sb.toString());
}
} catch (SQLException e) {
LOGGER.error("Sql exception " + e.getMessage());
}
}
printToCsv
public static void printToCsv(List<String> resultArray) throws Exception{
File csvOutputFile = new File(file_name);
FileWriter fileWriter = new FileWriter(csvOutputFile, false);
for(String mapping : resultArray) {
fileWriter.write(mapping + "\n");
}
fileWriter.close();
}
【讨论】：
-
这不会生成 CSV 文件（甚至没有“，”或“;”分隔符）。
-
很好，但我不喜欢“resultSetArray”实例变量。总是更喜欢参数和返回值而不是实例变量。
-
此代码不起作用（请参阅 resultArray。）此外，我不确定输出是否是所要求的，因为它不是真正的标准 CSV，而是在这里用空格分隔，并且没有出现成为任何转义分隔符的代码，因此 Excel 很可能无法读取由此产生的输出。也不确定这是否只是我的环境，但它似乎没有正确处理 dbnull 值。
这是一个例子：
import java.io.*;
import java.sql.*;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFCell;
public class ExcelFile {
public static void main(String[] args) {
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection connection = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/test", "root", "root");
PreparedStatement psmnt = null;
Statement st = connection.createStatement();
ResultSet rs = st.executeQuery("Select * from student");
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("Excel Sheet");
HSSFRow rowhead = sheet.createRow((short) 0);
rowhead.createCell((short) 0).setCellValue("Roll No");
rowhead.createCell((short) 1).setCellValue("Name");
rowhead.createCell((short) 2).setCellValue("Class");
rowhead.createCell((short) 3).setCellValue("Marks");
rowhead.createCell((short) 4).setCellValue("Grade");
int index = 1;
while (rs.next()) {
HSSFRow row = sheet.createRow((short) index);
row.createCell((short) 0).setCellValue(rs.getInt(1));
row.createCell((short) 1).setCellValue(rs.getString(2));
row.createCell((short) 2).setCellValue(rs.getString(3));
row.createCell((short) 3).setCellValue(rs.getInt(4));
row.createCell((short) 4).setCellValue(rs.getString(5));
index++;
}
FileOutputStream fileOut = new FileOutputStream("c:\\excelFile.xls");
wb.write(fileOut);
fileOut.close();
System.out.println("Data is saved in excel file.");
rs.close();
connection.close();
} catch (Exception e) {
}
}
}
【讨论】：
-
这不能应用于 OP 要求的 “任何 sql 查询结果”，因为每一列都以自定义方式处理。
为此，您需要编写一个可以占用任何查询和任何驱动程序的小代码。第一个输入应该是驱动程序名称，作为您正在编写的软件的输入。那么你正在编写的软件应该能够执行给它的任何 SQL，并且只给出行和列。
接下来的任务是解析来自java应用的JDBC的ResultSet。要么你想将结果写入 CSV 文件，要么 EXCEL 取决于你有多么好的 java api 来做到这一点。
将输出写入 CVS 很简单，而且并不繁琐。我还没有将数据导出到 Excel 中。我相信你会为此找到罐子。
【讨论】：
解决方案基于属性文件。
配置此选项的位置：
- 数据库的参数。
- 可选的额外 SQL Where 子句。
- 输出文件的参数。
进程可以同时启动bis 4个线程来下载4个表。 如果要再次运行，必须删除生成的文件。 还会创建一个包含过程数据的文本文件 (logs.txt)。
---- 属性文件：ExportProperties.prop --------- 该解决方案将在以下位置编写一个草图版本：
C:\tmp\test\ExportProperties.prop
## configuration properties
driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@ldap://localhost
username=user
password=pass
fileExtension=_20200623.csv
columSeparator=;
charsetName=CP1252
## export only 10 rows change to false
only10Rows=true
##tables
tableName.1=USER
tableName.1.sqlWhere= user.name IS NOT NULL
tableName.2=ROLL
tableName.3=FIRMA
---------主文件--------
public class ExportTable2CSVMain implements Runnable {
static SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss SSS|");
static final String folder = "C:\\tmp\\test\\";
static final Properties prop = getProperties();
public static void main(String[] args) {
for (int x = 1; x < 6; x++) {
try {
writieLog(0, "Start thread " + x);
new ExportTable2CSVMain();
Thread.sleep(1000);
} catch (final Exception e) {
e.printStackTrace();
}
}
}
public ExportTable2CSVMain() {
final Thread t = new Thread(this);
t.start(); // start the thread -> run
}
@Override
public void run() {
int pos = 1;
String tableName = prop.getProperty("tableName." + pos);
while (tableName != null) {
try {
export(tableName, pos++);
} catch (final Exception e) {
e.printStackTrace();
}
tableName = prop.getProperty("tableName." + pos);
}
}
private void export(String tableName, int filePos) throws Exception {
final boolean only10Rows = prop.getProperty("only10Rows", "false").equals("true");
String extraWhere = prop.getProperty("tableName."+filePos+".sqlWhere");
if(extraWhere ==null)
extraWhere = prop.getProperty("sqlWhere");
if(extraWhere ==null)
extraWhere = "";
final String sql = "select * from " + tableName + extraWhere
+ (only10Rows ? " FETCH NEXT 10 ROWS ONLY" : "");
final String fileName = folder + tableName + prop.getProperty("fileExtension");
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
ExportTable2CSV data2csv = null;
try {
data2csv = new ExportTable2CSV(fileName, tableName, filePos);
if (data2csv.toDo()) {
conn = getConnection();
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
data2csv.createFileCsv(rs);
}
} catch (final Exception e) {
final int row = data2csv == null ? -1 : data2csv.row;
writieLog(filePos, "SQL", "Error", "rows:" + row, tableName, e.getMessage());
e.printStackTrace();
} finally {
try {
rs.close();
} catch (final Exception e) {
}
try {
stmt.close();
} catch (final Exception e) {
}
try {
conn.close();
} catch (final Exception e) {
}
}
}
public Connection getConnection() throws Exception {
Class.forName(prop.getProperty("driver"));
return DriverManager.getConnection(//
prop.getProperty("url"),
prop.getProperty("username"),
prop.getProperty("password"));
}
static private Properties getProperties() {
File file = new File(folder);
if (!file.exists()) { // if the folder do not exist create it
file.mkdirs();
}
file = new File(folder + "ExportProperties.prop");
if (!file.exists()) {
try {
final PrintWriter out = new PrintWriter(
new BufferedWriter(new FileWriter(folder + "ExportProperties.prop", true)));
out.println(//
"## configuration properties\n" +
"driver=oracle.jdbc.driver.OracleDriver\n" +
"url=jdbc:oracle:thin:@ldap://localhost\n"+
"username=USER\n" +
"password=PASSWORD\n" +
"sqlWhere=\n" +
"fileExtension=_20200619.csv\n" +
"columSeparator=;\n" +
"charsetName=CP1252\n" +
"##tables\n" +
"tableName.1=USER\n" + //
"tableName.2=ROLL\n"
);
out.close();
} catch (final Exception e) {
e.printStackTrace();
}
}
final Properties prop = new Properties();
try {
prop.load(new FileInputStream(folder + "ExportProperties.prop"));
} catch (final IOException e) {
e.printStackTrace();
}
return prop;
}
public static void writieLog(int filePos, String... txt) throws Exception {
final PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(folder + "logs.txt", true)));
String sb = "";
sb += formatter.format(new Date()) + "\t";
sb += filePos == 0 ? "" : "F-" + filePos + "\t";
for (final String s : txt) {
sb += s + "\t";
}
System.out.println(sb);
out.println(sb);
out.close();
}
}
---------------- ExportTable2CSV 文件 -------
/**
* Created by Jose Manuel Davila (Mel) kailas.mel@gmail.com
*/
public class ExportTable2CSV {
final String fileName;
final String table;
final String columSeparator;
final Boolean columnName = true;
final int filePos;
int row = 0;
int column = 0;
public ExportTable2CSV(String fileName, String table, int filePos) {
this.filePos = filePos;
this.fileName = fileName;
this.table = table;
columSeparator = ExportTable2CSVMain.prop.getProperty("columSeparator", ";");
}
public boolean toDo() throws Exception {
if (new File(fileName).exists()) {// the file exist jet return
return false;
}
writeLine("");
return true;
}
public void createFileCsv(ResultSet rs) throws Exception {
String sb = "";
try {
ExportTable2CSVMain.writieLog(filePos, "FILE", "INI ", table, fileName);
// WRITE COLUMN NAME
final ResultSetMetaData rsmd = rs.getMetaData();
sb = "";
final List<String> list = new ArrayList<String>();
if (columnName) {
for (int i = 1; i <= rsmd.getColumnCount(); i++) {
sb += rsmd.getColumnName(i) + columSeparator;
list.add(rsmd.getColumnName(i));
}
writeLine(sb.toString());
}
// WRITE DATA
while (rs.next()) {
sb = "";
column = 0;
for (int i = 1; i <= rsmd.getColumnCount(); i++) {
final Object obj = rs.getObject(i);
String data = "";
if (obj != null) {
if (obj instanceof String) {
data = obj.toString();
if (data.indexOf(columSeparator) != -1) {
if (data.indexOf("\"") != -1) {
data = data.replaceAll("\"", "'");
ExportTable2CSVMain.writieLog(filePos, "FILE", "WITH comm and ; ", "row:" + row,
"Column:" + list.get(column), table, fileName);
}
data = "\"" + data + "\"";
}
} else {
data = obj.toString();
}
}
sb += data + columSeparator;
column++;
}
writeLine(sb.toString());
row++;
}
ExportTable2CSVMain.writieLog(filePos, "FILE", "END ", "rows:" + row, table, fileName);
} catch (final Exception e) {
ExportTable2CSVMain.writieLog(filePos, "FILE", "Error ", "rows:" + row, table, fileName, e.getMessage());
e.printStackTrace();
} finally {
if (rs != null) {
rs.close();
}
}
}
void writeLine(String line) throws Exception {
if (row > 0 && row % 1000 == 0) {
System.out.println(filePos + " " + row + " working ...");
}
final PrintWriter cname = new PrintWriter(new BufferedWriter((new OutputStreamWriter(
new FileOutputStream(fileName, true), ExportTable2CSVMain.prop.getProperty("charsetName", "CP1252")))));
if (line.equals("")) {
cname.print(line);
} else {
cname.println(line);
}
cname.close();
}
}
--------- POM 文件 pom.xml ----
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>ExportTable2CSV</groupId>
<artifactId>ExportTable2CSV</artifactId>
<version>1.1.0</version>
<name>ExportTable2CSV</name>
<properties>
<ojdbc8.version>18.3.0.0.0</ojdbc8.version>
</properties>
<dependencies>
<dependency>
<groupId>com.oracle</groupId>
<artifactId>ojdbc8</artifactId>
<version>${ojdbc8.version}</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</project>
导出到以制表符分隔的列。
在属性文件中更改此属性：
fileExtension=_mel.txt
columSeparator=\t
【讨论】：
这很好用：
PreparedStatement statement = famuat.prepareStatement(sql query);
ResultSet result = statement.executeQuery();
ResultSetMetaData md = result.getMetaData();
FileWriter fw = new FileWriter(filepath);
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
columnheader = md.getColumnName(i);
// System.out.println(columnheader);
if (i > 1) System.out.print(" | ");
if (i > 1) System.out.print(", ");
if (i > 1) System.out.print("\t");
fw.append(columnheader.toUpperCase());
fw.append(",");
System.out.println(columnheader);
}
while (result.next()) {
fw.append("\r\n");
for (int i = 1; i <= columnCount; i++) {
if (i > 1) System.out.print(" | ");
if (i > 1) System.out.print(", ");
if (i > 1) System.out.print("\t");
fw.append(result.getString(i));
fw.append(",");
row = result.getString(i);
System.out.println(row);
}
}
【讨论】：
这项工作用于导出到 csv 和 txt
public void ExportTxt(){
FileWriter texto = null;
ResultSet rs2 = null;
ResultSet rs = null;
try {
texto = new FileWriter("texto.txt");
PrintWriter pw = new PrintWriter(texto);
Statement consulta = conn.createStatement();
Statement consulta2 = conn.createStatement();
String query = "SELECT * FROM coches";
rs = consulta.executeQuery(query);
int i=1;
pw.println("----------------");
while (rs.next()) {
pw.println(i + ",Coche: Matricula:" + rs.getString("matricula") + ", Marca:" + rs.getString("marca") + ", Modelo:" + rs.getString("modelo"));
String query2 = "SELECT * FROM reparaciones WHERE coche = '" + rs.getString("matricula") + "'";
rs2 = consulta2.executeQuery(query2);
pw.println("----------------");
while(rs2.next()){
pw.println(rs2.getRow() + ",Reparacion: Fecha entrada:" + rs2.getString("fecha_entrada") + ", Fecha salida:" + rs2.getString("fecha_salida"));
}
i++;
}
rs.close();
rs2.close();
consulta.close();
} catch (IOException ex) {
Logger.getLogger(Conexion.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(Conexion.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
texto.close();
} catch (IOException ex) {
Logger.getLogger(Conexion.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
public void ExportCSV(){
PrintWriter pw = null;
try {
File archivo = new File("excel.csv");
pw = new PrintWriter((new FileWriter(archivo)));
Statement consulta = conn.createStatement();
String query = "SELECT * FROM clientes";
ResultSet rs = consulta.executeQuery(query);
pw.println("id;nombre;apellidos;direccion;nif;telefono");
while(rs.next()){
pw.println(rs.getInt("id") + ";" + rs.getString("nombre") + ";" + rs.getString("Apellidos") + ";" + rs.getString("direccion") + ";" + rs.getString("nif") + ";" + rs.getString("telefono"));
}
} catch (IOException ex) {
Logger.getLogger(Conexion.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(Conexion.class.getName()).log(Level.SEVERE, null, ex);
} finally {
pw.close();
}
}
【讨论】：
尝试了其他一些答案，但它们并没有真正起作用和/或要求添加库，我希望避免这种情况，尤其是对于像 CSV 这样简单的格式。
所以这是我自己的看法。没有特殊的库要求（除了您的 SQL 驱动程序），因此（大部分）vanilla Java 8 或更高版本应该可以工作。也适用于 beanshell（因此 try/finally 而不是 try-with-resources。）所有字段应该正确转义，假设我创建（发布）的 junit 测试是正确的，所以任何符合 RFC 4180 的 CSV阅读器应该能够在没有错误和/或出错的情况下解析它，并且就本代码而言，包括 Microsoft Excel。
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Connection;
import java.sql.Statement;
import java.util.List;
import java.util.ArrayList;
import java.io.FileWriter;
// Replace this with your own SQLServerDriver class
import com.microsoft.sqlserver.jdbc.SQLServerDriver;
public class Sandbox {
/**
* Replaces null with an empty string, surrounds values that have commas or
* newlines with quotes, and if a value begins with a quote it escapes any
* quotes with another quote
*
* @param value
* @return
*/
public String csvEscape(String value) {
if (value == null) {
value = "";
} else if (value.contains(",") || value.contains("\n") || value.startsWith("\"")) {
value = "\"" + value.replace("\"", "\"\"") + "\"";
}
return value;
}
/**
* Run an SQL query and dump the output into a CSV file as we receive it
*
* @param url URL to your server in a format that the driver expects, i.e.
* "jdbc:sqlserver://server.com:1433;IntegratedSecurity=true;databaseName=foo"
* @param statement SQL statement, i.e. "SELECT foo FROM bar". Do NOT pass user
* generated strings!
* @param csvPath File path to the csv file, i.e. /foo/bar.csv
* @throws SQLException
* @throws IOException
*/
public void sqlToCsv(String url, String statement, String csvPath) throws SQLException, IOException {
Connection connection = DriverManager.getConnection(url);
Driver driverSelect = new SQLServerDriver();
DriverManager.registerDriver(driverSelect);
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(statement);
ResultSetMetaData md = rs.getMetaData();
int colCount = md.getColumnCount();
List<String> cols = new ArrayList<String>();
for (int i = 1; i <= colCount; i++) {
String value = csvEscape(md.getColumnName(i));
cols.add(value);
}
List<String> row = new ArrayList<String>();
FileWriter fileWriter = null;
try {
fileWriter = new FileWriter(csvPath, false);
fileWriter.write(String.join(",", cols) + "\n");
while (rs.next()) {
row.clear();
for (int i = 1; i <= colCount; i++) {
String value = csvEscape(rs.getString(i));
row.add(value);
}
fileWriter.write(String.join(",", row) + "\n");
}
} finally {
fileWriter.close();
}
}
@Test
public void testCsvEscape() {
assertEquals("say \"cheese!\"", csvEscape("say \"cheese!\""));
assertEquals("\"\"\"say cheese\"\"!\"", csvEscape("\"say cheese\"!"));
assertEquals("\"cheese\nplease\"", csvEscape("cheese\nplease"));
assertEquals("\"cheese, please\"", csvEscape("cheese, please"));
assertEquals("\"say \"\"cheese,\n please!\"\"\"", csvEscape("say \"cheese,\n please!\""));
assertEquals("\"\"\"say \"\"cheese,\n please!\"\"\"\"\"", csvEscape("\"say \"cheese,\n please!\"\""));
}
}
【讨论】：