如何使用碧玉报告、图像上传在文件输入流中设置路径

Question

/

/error1： java.io.FileNotFoundException： jrxml\Blank_A4.jrxml (The 系统//找不到指定的路径(

错误 2：连接失败!! com.mysql.jdbc.exceptions.jdbc4.CommunicationsException： 通信//链路故障

我的编码'在这里输入代码

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Connection;
import java.util.HashMap;
import java.util.Map;
import net.sf.jasperreports.engine.JasperCompileManager;
import net.sf.jasperreports.engine.JasperExportManager;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.design.JasperDesign;
import net.sf.jasperreports.engine.xml.JRXmlLoader;
import net.sf.jasperreports.engine.JasperPrint;
import com.seerock.utils.DBConnection;

public class JasperReport {

static Connection conn;
public static void main(String[] args) throws FileNotFoundException {
    try{
        DBConnection db = new DBConnection();
        conn=db.getConnection();
        System.out.println("Loading Report Designs");
    //  InputStream input=new FileInputStream(new File("/jrxml/Blank_A4.jrxml"));
        InputStream input=new FileInputStream(new File("jrxml/Blank_A4.jrxml"));
        JasperDesign jasperDesign= JRXmlLoader.load(input);
        System.out.println("Compiling Report Designs");
        net.sf.jasperreports.engine.JasperReport jasperReport=JasperCompileManager.compileReport(jasperDesign);
        System.out.println("Creating JasperPrint Object");
        Map<String, String> parameters=new HashMap<String, String>();
        parameters.put("ReportTitle", "PDF JasperReport");

        JasperPrint jasperPrint=JasperFillManager.fillReport(jasperReport, null, conn); 
        //Exporting the report
        OutputStream output=new FileOutputStream(new File("report/Blank_A4.pdf"));
        JasperExportManager.exportReportToPdfStream(jasperPrint, output);
        System.out.println("Report Generation Complete");
        conn.close();
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
}
}

Answer 1

错误1

文件

需要存在，你需要指向它，文件在哪里，我指向什么???

试试这个...

File f = new File("report/Blank_A4.pdf");
System.out.println(f.getAbsolutePath());

错误 2.

连接功能，您没有

设法连接到数据库，URL，密码，用户名，端口可能是错误的，您没有包含DBConnection的代码，因此不可能说出您做错了什么。

请检查如何连接到数据库 JDBC 示例示例