在Java中String、int、Integer、Char、double类型转换

引言

java的类型转换相对比较简单，但对初学者来说，非常重要。下面一起来看一下吧~！

在Java中String、int、Integer、Char、double类型转换

1.如何将字符串String转换成整数int？

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		String s = "123456";
		int num = 0;		
		try {
			//num = Integer.valueOf(s).intValue();
			num = Integer.parseInt(s);
		  } catch (Exception e) {			
	     }
		 System.out.println(num);
	}
}

2.如何将字符创String转换成Integer？

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		String s = "123456";
		Integer integer = 0;		
		try {			
			integer = Integer.valueOf(s);
		  } catch (Exception e) {			
	     }
		 System.out.println(integer);
	}
}

3.如何将整数int转换成字符创String？

方法一：

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		int i = 123456;	
		String s= "";
		try {			
		   s = String.valueOf(i);
		  } catch (Exception e) {			
	     }
		 System.out.println(s);
	}
}

方法二：

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		int i = 123456;	
		String s= "";
		try {			
			s = Integer.toString(i); 
		  } catch (Exception e) {			
	     }
		 System.out.println(s);
	}
}

方法三：

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		int i = 123456;	
		String s= "";
		try {			
			s = "" + i;
		  } catch (Exception e) {			
	     }
		 System.out.println(s);
	}
}

4.如何将整数int转换成Integer？

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		int i = 123456;	
		Integer integer = 0;
		try {			
		integer= new Integer(i);
		  } catch (Exception e) {			
	     }
		 System.out.println(integer);
	}
}

5.如何将Integer转换成字符串String？

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		Integer integer = 123456;
		String s = "";
		try {			
			 s = integer.toString();
			 //s = String.valueOf(integer);
			 //s = "" + integer;
		  } catch (Exception e) {			
	     }
		 System.out.println(s);
	}
}

6.如何将Integer转换成int？

package s2s4;
public class Test {
	public static void main(String[] args) {
		
		Integer integer = 123456;
		int num = 0;
		try {			
			num= integer.intValue();		 
		  } catch (Exception e) {			
	     }
		 System.out.println(num);
	}
}

7.如何将String转换成BigDecimal？

package s2s4;
import java.math.BigDecimal;
public class Test {
	public static void main(String[] args) {
		
		String s = "123456";
		BigDecimal d_id = new BigDecimal(s);	
		 System.out.println(d_id);
	}
}

8.如何将String转换成char？

package s2s4;
import java.math.BigDecimal;
public class Test {
	public static void main(String[] args) {
		
		String s = "123456";
		char[] ac =s.toCharArray();
		 System.out.println(ac);
	}
}

9.如何将char转换成String？

package s2s4;

import java.math.BigDecimal;

public class Test {
	public static void main(String[] args) {
		
		char[] ac = {1,2,3,4,5,6};
		String s= ""; 
		try {
			s= ac.toString(); 
		  } catch (Exception e) {			
		 }
		 System.out.println(s);
	}
}

作者：Roger_CoderLife

链接：https://blog.csdn.net/Roger_CoderLife/article/details/80783279

本文为Roger_CoderLife的原创文章，著作权归作者所有，转载请注明原文出处，欢迎转载！