Struts2自定义Result（二）- StrutsResultSupport

在上篇博客中的图片可以看到，Struts有一个基本的抽象类，我们也可以继承他来自定义Result

继承他之后，只需要实现一个方法就可以了：

@Override
	protected void doExecute(String finalLocation, ActionInvocation invocation) throws Exception {
		
	}

这里简单说一下，怎样实现一个返回JSON串的Result

方法1：

自定义的Result

package org.ygy.demo.result;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import net.sf.json.JsonConfig;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.StrutsResultSupport;

import com.opensymphony.xwork2.ActionInvocation;

/**
 * 
 * @author yuguiyang
 * @description 返回JSON
 * @time 2013-9-4
 * @version V1.0
 */
public class JsonResult extends StrutsResultSupport {
	private static final long serialVersionUID = 2232581955223674065L;

	private Object result;
	private JsonConfig jsonConfig;
	
	public JsonResult() {}

	public JsonResult(JsonConfig jsonConfig) {
		super();
		this.jsonConfig = jsonConfig;
	}

	public Object getResult() {
		return result;
	}

	public void setResult(Object result) {
		this.result = result;
	}

	@Override
	protected void doExecute(String finalLocation, ActionInvocation invocation) throws Exception {
		HttpServletResponse response = null;
		try {
			response = ServletActionContext.getResponse();
			PrintWriter printWriter = response.getWriter();

			if (jsonConfig != null) {
				printWriter.write(JSONObject.fromObject(result, jsonConfig).toString());
			} else {
				printWriter.write(JSONSerializer.toJSON(result).toString());
			}
		} catch (Exception e) {
			throw new Exception("json parse error!");
		} finally {
			response.getWriter().close();
		}

	}

}

这里使用json-lib来将对象转换成JSON串

Action中是这样的：

注意：这里的返回值，就是刚才自定义的JsonResult

	public JsonResult ha() {
		System.out.println("--from ha().");
		
		List<String> msgs = new ArrayList<String>();
		msgs.add("one");
		msgs.add("two");
		msgs.add("three");
		
		JsonResult result = new JsonResult();
		result.setResult(msgs);
		
		return result;
	}

配置文件是这样的：

		<action name="ha" class="org.ygy.demo.result.HelloAction" method="ha">
			<result name="success" type="json" >/hello.jsp</result>
		</action>

PS:这里有点儿乱，明天在研究一下吧

方法二：

package org.ygy.demo.result;

import java.util.ArrayList;
import java.util.List;

import com.opensymphony.xwork2.ActionSupport;

public class HelloAction extends ActionSupport {
	private static final long serialVersionUID = 6422231025855671997L;
	
	private Person person;
	
	public String say() {
		System.out.println("--from say().");
		
		
		return SUCCESS;
	}
	
	public String go() {
		System.out.println("--from go().");
		
		return SUCCESS;
	}
	
	public JsonResult ha() {
		System.out.println("--from ha().");
		
		List<String> msgs = new ArrayList<String>();
		msgs.add("one");
		msgs.add("two");
		msgs.add("three");
		
		JsonResult result = new JsonResult();
		result.setResult(msgs);
		
		return result;
	}
	
	public String haha() {
		person = new Person(100 , "拉速度");
		
		return SUCCESS;
	}
	
	public Person getPerson() {
		return person;
	}

	public void setPerson(Person person) {
		this.person = person;
	}
	
}

自定义Result：

package org.ygy.demo.result;

import java.io.PrintWriter;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONSerializer;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.StrutsResultSupport;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.util.ValueStack;

public class JsonResult2 extends StrutsResultSupport {
	private static final long serialVersionUID = -6528161012160891182L;

	@Override
	protected void doExecute(String finalLocation, ActionInvocation invocation) throws Exception {
		ActionContext context = invocation.getInvocationContext();
		
		//通过invocation获取Action的变量 
		Map<String , Object> temp = context.getContextMap();
		
		Object action = invocation.getAction();
		
		 ValueStack stack = invocation.getStack();
         Object rootObject = stack.findValue("person");
         if(rootObject instanceof Person) {
        	 System.out.println("I get it.");
         }
         
		//转换为JSON字符串
		
		HttpServletResponse response = ServletActionContext.getResponse();
		PrintWriter out = response.getWriter();
		
		out.println(JSONSerializer.toJSON(rootObject).toString());
		out.println(JSONSerializer.toJSON((Person)rootObject).toString());
		
		out.flush();
		out.close();
	}

}

配置文件：

		<action name="haha" class="org.ygy.demo.result.HelloAction" method="haha">
			<result name="success" type="json2">/do you know me</result>
		</action>

这一次，在自定义Result时，在在值栈中找到变量Person，Struts有自己实现的JSONResult，大家可以看一下源码。

这里越写越乱，以后再梳理一下。