java mysql不会写入数据库

我用java应用程序编写了一个程序，它使用u表和DB

当我不想向数据库中添加值时，什么也没有发生

下面是连接和写入DB的代码

import java.sql.*;

/**
 *
 * @author alexa
 */
public class DatabaseManager {

private static Connection connect = null;

public static Boolean ConnectToDatabase()
{
    try
    {
        Class.forName("com.mysql.jdbc.Driver");
        // Setup the connection with the DB
        connect = DriverManager.getConnection("jdbc:mysql://localhost/sdb?user=ShiftPilot&password=bunker");

        return true;

    }catch(Exception e)
    {
        return false;
    }
}

public static ResultSet GetTenLastResult()
{
    return null;
}

public static Boolean SearchProblem()
{
    if(ConnectToDatabase()) // if connection ok and saved
    {


    }
    else
        {
        return false;
    }
    return false;
}    
public static Boolean SaveMeasuring(String date, String name, String size, String no_production, String grid, String adjust_grid, String adjust_grid2, 
        String thikness, String link_plans_tiles ,String visual_control_white_lines, String visual_control_waves, String adjust_link, String lenght_above,
        String lenght_below, String with_left, String with_right, String angularity_left, String angularity_right, String adjust_measuring, String date_print, 
        String measuring_mousse_s3, String measuring_mousse_s7, String adjust_mousse, String plank_asside_tracking, String cut1_6, String cut2_5, String cut3_8,
        String cut4_7, String cut1_2, String cut3_4, String cut5_6, String cut7_8, String bevel_1, String bevel_3, String bevel_5, String bevel_7)
{
    // save strings to database
    if(ConnectToDatabase()) // if connection ok and savd
    {
        // create a Statement from the connection

        try
        {
        // insert the data

            PreparedStatement  statement;
            statement = connect.prepareStatement("INSERT INTO measuring (date, name, size, no_production, grid, adjust_raster, adjust_raster2, thinkness, link_plans_tiles, visual_control_white_lines, visual_control_waves, adjust_link, lenght_above, lenght_below, with_left, with_right, angularity_left, angularity_right, adjust_measuring, date_print, measuring_mousse_s3, measuring_mousse_s7, adjust_mousse, plank_asside_tracking, cut1_6, cut2_5, cut3_8, cut4_7, cut1_2, cut3_4, cut5_6, cut7_8, bevel_1, bevel_3, bevel_5, bevel_7) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)");
            statement.setString(1, date);
            statement.setString(2, name);
            statement.setString(3, size);
            statement.setString(4, no_production);
            statement.setString(5, grid);
            statement.setString(6, adjust_grid);
            statement.setString(7, adjust_grid2);
            statement.setString(8, thikness);
            statement.setString(9, link_plans_tiles);
            statement.setString(10, visual_control_white_lines);
            statement.setString(11, visual_control_waves);
            statement.setString(12, adjust_link);
            statement.setString(13, lenght_above);
            statement.setString(14, lenght_below);
            statement.setString(15, with_left);
            statement.setString(16, with_right);
            statement.setString(17, angularity_left);
            statement.setString(18, angularity_right);
            statement.setString(19, adjust_measuring);
            statement.setString(20, date_print);
            statement.setString(21, measuring_mousse_s3);
            statement.setString(22, measuring_mousse_s7);
            statement.setString(23, adjust_mousse);
            statement.setString(24, plank_asside_tracking);
            statement.setString(25, cut1_6);
            statement.setString(26, cut2_5);
            statement.setString(27, cut3_8);
            statement.setString(28, cut4_7);
            statement.setString(29, cut1_2);
            statement.setString(30, cut3_4);
            statement.setString(31, cut5_6);
            statement.setString(32, cut7_8);
            statement.setString(33, bevel_1);
            statement.setString(34, bevel_3);
            statement.setString(35, bevel_5);
            statement.setString(36, bevel_7);
            statement.executeUpdate();
        }
        catch(Exception e)
        {
            return false;
        }

        return true;
    }
    else
    {
        return false;
    }
}

这是jbutton用来向DB发送数据的代码

private void jButtonAddMeasuring1ActionPerformed(java.awt.event.ActionEvent evt) {                                                     
    String adr1 = (jComboBoxAdjustGrid1.getSelectedItem().toString() + ": " + jTextFieldAdjustGrid1);
    String adr2 = (jComboBoxAdjustGrid2.getSelectedItem().toString() + ": " + jTextFieldAdjustGrid2);
    if (DatabaseManager.SaveMeasuring(jLabelClock1.getText(), jComboBoxName1.getSelectedItem().toString(),jComboBoxType.getSelectedItem().toString(), noP,
            jComboBoxGrid.getSelectedItem().toString(), adr1, adr2, jTextFieldThickness.toString(), jComboBoxTylesGeneral.getSelectedItem().toString(),
            jComboBoxVisualControlLines.getSelectedItem().toString(), jComboBoxVisualControlWave.getSelectedItem().toString(), jTextFieldLinkAdjust.toString(),
            jTextFieldLenghtLeft.toString(), jTextFieldLenghtRight.toString(), jTextFieldWithLeft.toString(), jTextFieldWithRight.toString(), jTextFieldAngularityLeft.toString(),
            jTextFieldAngularityRight.toString(), jTextFieldMeasuringAdjust.toString(), jComboBoxDatePrint.getSelectedItem().toString(), jTextFieldMousse1.toString(),
            jTextFieldMousse2.toString(), jTextFieldMousseAdjust.toString(), jComboBoxTracking.getSelectedItem().toString(), jComboBoxCutting1.getSelectedItem().toString(), 
            jComboBoxCutting2.getSelectedItem().toString(), jComboBoxCutting3.getSelectedItem().toString(), jComboBoxCutting4.getSelectedItem().toString(),
            jComboBoxCutting5.getSelectedItem().toString(), jComboBoxCutting6.getSelectedItem().toString(), jComboBoxCutting7.getSelectedItem().toString(),
            jComboBoxCutting8.getSelectedItem().toString(), jComboBoxBevel1.getSelectedItem().toString(), jComboBoxBevel2.getSelectedItem().toString(),
            jComboBoxBevel3.getSelectedItem().toString(), jComboBoxBevel4.getSelectedItem().toString())){
        ok k=new ok();
        k.setVisible (true);
    }else {
        error o=new error();
        o.setVisible (true);
    };}

---

我做错了什么？

1。捕获异常时打印堆栈跟踪。2.添加适当的日志记录。3.调试。欢迎使用SO。调试=拆分并征服：检查您的连接。如果连接正常，请尝试执行简单的执行更新，如果正常，请检查按钮操作侦听器中的代码输出……尤其是所有这一切都可能是由于调用的任何

getSelectedItem（）.toString（）

的

NullPointerException

。您最好的选择是在这里使用调试器，如前所述。此外（只是一个建议，但无助于回答您的问题），您可能希望为

SaveMeasuring

方法提供较少的参数。例如，您可以创建一个类，使对象将这些参数保存到字段中。