Question

如果找不到我输入的数据，我想处理它。但是，当找不到数据时，程序将重复打印消息。我应该在哪里正确地使用else语句？

public void Data(String x){
    for (int i = 1; i < 6; i++) {
        if (x.equalsIgnoreCase(table1[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table1[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table2[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table2[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table3[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table3[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table4[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table4[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table5[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table5[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table6[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table6[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table7[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table7[i][j]);
            }
        }
        else System.out.println("Data not found!");
    }
}

Answer 1

试试这个：

public void Data(String x){
    boolean b = false;
    for (int i = 1; i < 6; i++) {
        if (x.equalsIgnoreCase(table1[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table1[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table2[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table2[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table3[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table3[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table4[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table4[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table5[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table5[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table6[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table6[i][j]);
            }
        }
        else if (x.equalsIgnoreCase(table7[i][1])){
            for (int j = 0; j < 4; j++) {
                System.out.printf("|%-40s", table7[i][j]);
            }
        }
        else b = true;
    }
    if (b) System.out.println("Data not found!");
}

Answer 2

如果您想在找不到数据后立即终止，可以将您的else语句更改为：

else {
    System.out.println("Data not found!");
    return;
}

Java - 将else语句放入循环中

2 个答案: