java-resultset.next()循环中的打印语句不打印

这是将Java JDBC与Oracle数据库一起使用.

if (rset.next()){
    // At this point, there are reviews to show                                                                                                          
    int rinc = 0;
    String seenextreviews = "y";
    System.out.println("Rating - Text - Reviewer - RDate");
    while(rset.next()){
        // Iterate through the result set                                                                                                                
        System.out.println("Increment: " + rinc);
        if(rinc % 3 == 0) {
            // Displayed 3 reviews                                                                                                                       
            seenextreviews = "maybe";
            while(!seenextreviews.equals("y") && !seenextreviews.equals("n")){
                seenextreviews = console.readLine("See next reviews (y/n)? ");
                if (!seenextreviews.equals("y") && !seenextreviews.equals("n")){
                    System.out.println("Invalid input '" + seenextreviews + "'");
                }
            }
            if (seenextreviews.equals("n")) {
                System.out.println("Breaking...");
                break;
            } else {
                System.out.println("Continue...");
            }
        }
        System.out.println(rset.getInt("rating") + " - " + 
            rset.getString("text") + " - " + 
            rset.getString("reviewer") + " - " + 
            rset.getString("rdate"));
        rinc = rinc + 1;
    }
}

对于给定的代码,仅“ if(rset.next())”内的所有“ System.out.println(values)”都为System.out.println(“ Invalid input’” seeedreviews“’”);和System.out.println(rset.getInt(“ rating”)…);打印,而其他所有内容都不打印.

但是,console.readLine(“ text”)仍会在询问用户输入之前打印文本.

为什么我的打印报表不打印？将查询更改为一次选择3行并调用多个查询的唯一替代方法是吗？

For the given code, all of the ‘System.out.println(values)’ within ‘if (rset.next())’ only

从ResultSet#next

Moves the cursor froward one row from its current position.

因此,看起来您的查询返回了一行,并且您在if(rset.next())条件下进行了读取,而转到了从第二行到末尾读取的while(rset.next())时,但是由于您没有第二行要读取,因此while循环结束.

可能的解决方案：使用标志来打印标题：

int rinc = 0;
String seenextreviews = "y";
while(rset.next()) {
    //this serves as flag
    if (rinc == 0) {
        System.out.println("Rating - Text - Reviewer - RDate");
    }
    //rest of your code logic...
}