Java自定义异常与异常使用最佳实践

        若要在异常中添加附加信息，则可以为类添加一些变量和方法。本例演示的自定义异常没有按照业务类型来命名，而是创建一个通用异常类，以retCd来区别发生异常的业务类型与发生位置，当然对于具体的retCd值，事先必须有具体的规定或说明。

/**
 * 多数情况下，创建自定义异常需要继承Exception，本例继承Exception的子类RuntimeException
 * @author Mahc
 *
 */
public class CustomerException extends RuntimeException {

	private String retCd ;  //异常对应的返回码
	private String msgDes;  //异常对应的描述信息
	
	public CustomerException() {
		super();
	}

	public CustomerException(String message) {
		super(message);
		msgDes = message;
	}

	public CustomerException(String retCd, String msgDes) {
		super();
		this.retCd = retCd;
		this.msgDes = msgDes;
	}

	public String getRetCd() {
		return retCd;
	}

	public String getMsgDes() {
		return msgDes;
	}
}

public class TestClass {

	public void testException() throws CustomerException {
		try {
<p>			//..some code that throws <span style="font-family:SimSun;">CustomerException</span></p>		} catch (Exception e) {
			throw new CustomerException("14000001", "String[] strs's length < 4");
		}
	}
}

public class TestCustomerException {

	public static void main(String[] args) {

		try {
			TestClass testClass = new TestClass();
			testClass.testException();
		} catch (CustomerException e) {
			e.printStackTrace();
			System.out.println("MsgDes\t"+e.getMsgDes());
			System.out.println("RetCd\t"+e.getRetCd());
		}
	}
}

public void dataAccessCode (){
    Connection conn = null;
    try{
        conn = getConnection ();
        ..some code that throws SQLException
    }catch(SQLException ex){
        ex.printStacktrace ();
    } finally{
        DBUtil.closeConnection (conn);
    }
}
 class DBUtil{
    public static void closeConnection
        (Connection conn){
        try{
            conn.close ();
        } catch(SQLException ex){
            logger.error ("Cannot close connection");
            throw new RuntimeException (ex);
        }
    }
}

public void useExceptionsForFlowControl () {
    try {
        while (true) {
            increaseCount ();
        }
    } catch (MaximumCountReachedException ex) {
    }
    //Continue execution }
 public void increaseCount ()
    throws MaximumCountReachedException {
    if (count >= 5000)
        throw new MaximumCountReachedException ();
}

try{
..
}catch(Exception ex){
}

【转载使用，请注明出处：http://blog.csdn.net/mahoking】

【转载使用，请注明出处：http://blog.csdn.net/mahoking】

Java自定义异常与异常使用最佳实践

原文：http://blog.csdn.net/mahoking/article/details/45064259