Struts2---声明式异常处理

在service方法里 throw抛出一个异常, 然后再方法声明上加上throws:

public List<Category> list() throws SQLException{

		Connection conn=DB.createConn();

		String sql = "select * from  _category";

		PreparedStatement ps = DB.prepare(conn, sql);

		List<Category> categories =  new ArrayList<Category>();

		try {

			 ResultSet rs=ps.executeQuery();

			 Category c = null;

			 while(rs.next()){

				 c =new Category();

				 c.setId(rs.getInt("id"));

				 c.setName(rs.getString("name"));

				 c.setDescription(rs.getString("description"));

				 categories.add(c);

			 }

		} catch (SQLException e) {

			e.printStackTrace();

			throw(e);

		}

		DB.close(ps);

		DB.close(conn);

		return categories;

	}

在调用list方法的action里 throws, 这样就不用try catch而是由struts2处理:

	public String list() throws Exception{

		categories=categoryService.list();

		return SUCCESS;

	}

struts.xml里如何配置?

 <package name="admin" namespace="/admin" extends="struts-default" >

    <default-action-ref name="index"/>

   		<action name="index">

   			<result>/admin/index.html</result>

   		</action>

       <action name="*_*" class="com.bjsxt.bbs2009.action.{1}Action" method="{2}">

       		<result>/admin/{1}_{2}.jsp</result>

       		<result name="input">/admin/{1}_{2}.jsp</result>

       		<exception-mapping result="error" exception="java.sql.SQLException"/>

       			<result name="error">/error.jsp</result>

       		<result name="exception_handle">/admin/exception.jsp</result>

       </action>

    </package>

service里的sql语句改成错误的, 这样在调用页面的时候, 就会显示error.jsp.

下面是异常处理最常用的方法:

1. 配置新的package, global results, global-exception-mappings, 自己的action的包继承异常包即可.

原理:::拦截器　

<package name="bbs2009_default" extends="struts-default">

	<global-results>

		<result name="error">/error.jsp</result>

	</global-results>

	<global-exception-mappings>

    		<exception-mapping result="error" exception="Exception"></exception-mapping>

    	</global-exception-mappings>

	</package>

    <package name="admin" namespace="/admin" extends="bbs2009_default" >

    <default-action-ref name="index"/>

   		<action name="index">

   			<result>/admin/index.html</result>

   		</action>

       <action name="*_*" class="com.bjsxt.bbs2009.action.{1}Action" method="{2}">

       		<result>/admin/{1}_{2}.jsp</result>

       		<result name="input">/admin/{1}_{2}.jsp</result>

        		<!--<exception-mapping result="error" exception="java.sql.SQLException"/>

       			<result name="error">/error.jsp</result>-->

       		<result name="exception_handle">/admin/exception.jsp</result>

       </action>

    </package>

巴特西

Struts2---声明式异常处理

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