Question

我不是Java的初学者，但我也不是专家。有没有办法缩短这些代码，以便占用更少的空间和可能更少的行？

JOptionPane.showMessageDialog(null, "The student's names are: " 
  + roster[0][0] + " " + roster[1][0] + ", " 
  + roster[0][1] + " " + roster[1][1] + ", " 
  + roster[0][2] + " " + roster[1][2] + ", and " 
  + roster[0][3] + " " + roster[1][3] + ".");

Answer 1

让我们一步一步地重构代码

引入变量以删除重复。

T[] col1 = roster[0];
T[] col2 = roster[1];

String content = col1[0] + " " + col2[0] + ", "
        + col1[1] + " " + col2[1] + ", "
        + col1[2] + " " + col2[2] + ", and "
        + col1[3] + " " + col2[3] + ".";

JOptionPane.showMessageDialog(null,"The student's names are: " + content);

将字符串连接分成多个赋值，然后除最后一个赋值外，所有赋值都相同。

int i = 0;
String content = "";
content += col1[i] + " " + col2[i] + ", ";i++;
content += col1[i] + " " + col2[i] + ", ";i++;
content += col1[i] + " " + col2[i] + ", ";i++;
content += "and " + col1[i] + " " + col2[i] + ".";i++;

使用三元运算符使多分配保持一致。

int i = 0;
String content = "";
content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", "); i++;
content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", "); i++;
content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", "); i++;
content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", "); i++;

使用while循环删除重复。

int i = 0;
String content = "";
while(i<=3) {
    content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", "); 
    i++;
}

用for-loop替换while循环。

String content = "";
for (int i = 0; i <= 3; i++) {
    content+= (i==3?"and ":"") + col1[i]+" "+col2[i] + (i==3?".":", ");
}

引入变量以使代码更具可读性。

String content = "";
for (int i = 0; i <= 3; i++) {
    String prefix = i == 3 ? "and " : "";
    String current = col1[i] + " " + col2[i];
    String suffix = i == 3 ? "." : ", ";
    content += prefix + current + suffix;
}

内联变量col1＆amp;仅使用一次的col2：

String content = "";
for (int i = 0; i <= 3; i++) {
    String prefix = i == 3 ? "and " : "";
    String current = roster[0][i] + " " + roster[1][i];
    String suffix = i == 3 ? "." : ", ";
    content += prefix + current + suffix;
}

用常量替换幻数3，最终代码如下：

final int last = 3;
String content = "";
for (int i = 0; i <= last; i++) {
    String prefix = i == last ? "and " : "";
    String suffix = i == last ? "." : ", ";
    String current = roster[0][i] + " " + roster[1][i];
    content += prefix + current + suffix;
}

JOptionPane.showMessageDialog(null, "The student's names are: " + content);

Answer 2

StringBuilder message = new StringBuilder("The student's names are: ");
for (int i = 0; i < roster[0].length; i++) {
    message
        .append(roster[0][i])
        .append(" ")
        .append(roster[1][i]);
    if (i < roster[0].length - 1)
        message.append(", ");
    if (i == roster[0].length - 2)
        message.append("and ")
}
message.append(".");
JOptionPane.showMessageDialog(null, message.toString());

可能就是这样的。正如您所看到的，您并没有真正保存任何行，但显然代码更灵活，因为它可以占用可变长度的名单。

Answer 3

您可以执行以下操作：最初分配您不想重复的正常语句。然后循环通过名册。

String rosterString= "The student's names are: ";
for(int i=0;i<= roster.length;i++){
    for(int j=0;j<= roster[i].length;j++){
         rosterString += (roster[i][j] + " ");
         if (i == 1 && j < 2) {
             rosterString += ", ";
         }
         else if (i == 1 && j == 2) {
             rosterString += ", and";
         }
         else if (i == 1 && j == 3) {
             rosterString += ".";
         }
         else {
             rosterString += " ";
         }
    }
}

然后将rosterString传递给您的方法。

Answer 4

String rosterString = "";
for(int i = 0; i < roster[0].length; i++) {
    rosterString += roster[0][i] + " " + roster[1][i] + ", ";
}

该代码将创建一个包含名称和逗号的字符串。然后，您可以添加if语句以检查它是否接近结束，以将,更改为and或.

是否可以缩短此代码？

4 个答案:

让我们一步一步地重构代码