if语句包含一个布尔表达式和一条或多条语句。
if statement - 语法
if(Boolean_expression) { //如果布尔表达式为真,语句将执行 }
if statement - 流程图

if statement - 示例
public class Test {
public static void main(String args[]) {
int x=10;
</span><span class="kwd">if</span><span class="pun">(</span><span class="pln"> x </span><span class="pun"><</span><span class="pln"> </span><span class="lit">20</span><span class="pln"> </span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="str">"This is if statement"</span><span class="pun">);</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
}
}
这将产生以下输出-
This is if statement.