0

错误是：

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以在 sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl. java:39) 在 sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 在 java.lang.reflect.Constructor.newInstance(Constructor.java:513) 在 com.mysql.jdbc.Util.handleNewInstance(Util.java :411) 在 com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052) 在 com.mysql.jdbc 的 com.mysql.jdbc.Util.getInstance(Util.java:386)。

代码是：

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    String bookid = jTextField2.getText();
    String doi = "";
    Calendar cal = new GregorianCalendar();
    doi = doi + cal.get(Calendar.YEAR) + "-" + cal.get(Calendar.MONTH) + "-" + cal.get(Calendar.DAY_OF_MONTH);
    String sql = "insert into library.issue values ('"+ bookid + "','librarian','"+ username + "','" + doi + "')";
    try
    {
        int i = st.executeUpdate(sql);
        if(i>0)
           JOptionPane.showMessageDialog(null,"BOOK IS ISSUED","SUCCESS",JOptionPane.PLAIN_MESSAGE);
        else
           JOptionPane.showMessageDialog(null,"problem in issuing book","FAILURE",JOptionPane.ERROR_MESSAGE);
        bookid = bookid.toUpperCase();
        String sql1 = "update library.books set status = " + 1 + "where book_id = '" + bookid + "'";
        PreparedStatement pstmt=c.prepareStatement(sql1);
        int j= pstmt.executeUpdate() ;
        //int j = st.executeUpdate(sql1);
    }
    catch(Exception ex)
    {
        ex.printStackTrace();
    }
}
4

2 回答 2

2

在 之前插入一个空格where：

String sql1 = "update library.books set status = " + 1 
      + " where book_id = '" + bookid + "'";
于 2012-04-07T21:31:31.593 回答
0

检查一次应该是

String sql1 = "update library.books set status =  1 where book_id = '" + bookid + "'";
于 2012-04-07T21:37:49.297 回答