JTable出现SQLite语法错误

Question

你好，我想用SQLite数据库创建一个JTable。数据应该来自一个SQLite数据库，并存储在这个。现在，在文本字段中输入新的细节。但是，我得到错误消息:“java.sql.SQLException: near”(“:语法错误”

怎么了？

    public class SQLite     {

public static DefaultTableModel model = new DefaultTableModel();
private static JTextField fieldID;
private static JTextField fieldName;
private static JTextField fieldAge;
private static JTextField fieldAddress;
private static JTextField fieldSalary;

公共静态void main（String args[]）{

Connection c = null;
Statement stmt = null;
try {
  Class.forName("org.sqlite.JDBC");
  c = DriverManager.getConnection("jdbc:sqlite:test.db");
  c.setAutoCommit(false);
  System.out.println("Opened database successfully");

  stmt = c.createStatement();

  c.commit();

  JFrame f = new JFrame();
  f.setLayout(new GridLayout(5,1));
  f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

  fieldID = new JTextField("ID");
  fieldName = new JTextField("Name");
  fieldAge = new JTextField("Age");
  fieldAddress = new JTextField("Address");
  fieldSalary = new JTextField("Salary");

  String sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
          "VALUES (fieldID.getText(), feldName.getText(), Age.getText(), feldAddress.getText(), feldSalary.getText()";
  stmt.executeUpdate(sql);

  JTable table = new JTable(model);
  f.add( new JScrollPane( table ) );

  model.addColumn("id");
  model.addColumn("name");
  model.addColumn("age");
  model.addColumn("address");
  model.addColumn("salary");

  ResultSet rs = stmt.executeQuery( "SELECT * FROM COMPANY;" );
  while ( rs.next() ) {
     int id = rs.getInt("id");
     String  name = rs.getString("name");
     int age  = rs.getInt("age");
     String  address = rs.getString("address");
     float salary = rs.getFloat("salary");

        model.addRow(new Object[] {id, name, age, address, salary});
  }

  /**JTextField feldID = new JTextField("ID");
  JTextField feldName = new JTextField("Name");
  JTextField feldAge = new JTextField("Age");
  JTextField feldAddress = new JTextField("Address");
  JTextField feldSalary = new JTextField("Salary");
    **/

  f.pack();
  f.setVisible( true );

  rs.close();
  stmt.close();
  c.close();
} catch ( Exception e ) {
  System.err.println( e.getClass().getName() + ": " + e.getMessage() );
  System.exit(0);
}
System.out.println("Operation done successfully");
}
}

Answer 1

使用准备语句。它更容易编码和维护，并将为您管理分隔符：

String sql = "INSERT INTO COMPANY (ID, NAME, AGE, ADDRESS, SALARY) VALUES (?, ?, ?, ?, ?)";

PreparedStatement stmt = connection.prepareStatement(sql);

stmt.setString( 1, fieldID.getText() );
stmt.setString( 2, fieldname.getText() );
stmt.setString( 3, ... );
stmt.setString( 4, ... );
stmt.setString( 5, ... );
stmt.executeUpdate();

但现在我得到 java sql 异常： “没有这样的列： ID”

嗯，这个信息是不言而喻的。没有“ID”列。我们无法帮助您，因为只有您知道这些列的正确名称，因为您是创建数据库的人。

Answer 2

这就是你的问题：

"VALUES (fieldID.getText(), feldName.getText(), Age.getText(), feldAddress.getText(), feldSalary.getText()";

它们被解读为垃圾，而不是对getter的引用。

下面是您必须使用串联替换它的内容。

"VALUES（"fieldID.getText () "," feldName.getText () "," Age.getText () "," feldAddress.getText () "," feldSalary.getText () ");";