What are the alignment methods in java?

In Java, alignment is used to specify the arrangement of strings and values ​​in text, including left alignment, right alignment, and center alignment. Use the "%s" format specifier for left justification, "%-s" for right justification, and "%1$s %-1$s" for center justification. Alignment can be specified using the String.format() method and the printf() method, which can also be used to align numeric values.

Java Alignment

In Java, alignment is used to specify the placement of strings and values ​​in text. Arrangement. Java provides the following alignment options:

Left-aligned (LEFT)

Using the %s format specifier, the string or value will be left aligned Align, i.e. start from the left side of the text.

<code class="java">System.out.printf("%s %s", "姓名", "小明");
// 输出：姓名 小明</code>

Right-aligned(RIGHT)

Using the %-s format specifier, the string or value will be right-aligned, that is, from the beginning of the text Start on the right.

<code class="java">System.out.printf("%-s %-s", "姓名", "小明");
// 输出：小明 姓名</code>

Centered alignment (CENTER)

Use %1$s and %-1$s format specifiers A combination of strings or numeric values ​​will be centered.

<code class="java">System.out.printf("%1$s %-1$s", "姓名", "小明");
// 输出：  姓名 小明  </code>

Format string alignment

You can also use the String.format() method to format a string and specify the alignment.

<code class="java">String name = String.format("%15s", "小明");
// "name" 的值为 "     小明"，以 15 个空格右对齐。</code>

Format numerical alignment

For numerical values, you can use the %d, of the printf() method The %f or %e format specifier specifies alignment.

<code class="java">// 格式化为右对齐的整数
System.out.printf("%8d", 123);
// 输出：    123

// 格式化为左对齐的小数
System.out.printf("%-8.2f", 123.456);
// 输出：123.45</code>

Example

The code example below demonstrates different alignments:

<code class="java">String name = "小明";
int age = 20;
double salary = 12345.67;

System.out.printf("%s %d %f\n", name, age, salary);          // 左对齐
System.out.printf("%-s %-d %-f\n", name, age, salary);      // 右对齐
System.out.printf("%1$s %-1$d %.2f\n", name, age, salary);  // 居中对齐</code>

Output:

<code>小明 20 12345.670000
小明2012345.670000
   小明  20  12345.67</code>

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