struts1+json的应用

struts1不像struts2一样，并未对json做集成，因此要使用json就必须自己写代码实现json对象的封装，可以在BaseAction中写一个共通方法，用于封装后台的数据为json对象并发送到前台：

public class BaseAction extends Action{

	private String encoding = "UTF-8";
	private String contentType = "application/json";
	
	/**
	 * to make JSON object that will be returned to the front-end and send it
	 * 
	 * @param response response
	 * @param objName jsonObjectName
	 * @param obj object that is used to make jsonObject
	 * @throws IOException
	 */
	protected void makeJSONObject(HttpServletResponse response, String objName, Object obj) throws IOException {

		this.contentType = contentType + ";charset=" + encoding;
		LogUtil.log.info("Set contentType to: " + contentType);
		
		JSONObject jsonObj = new JSONObject();
		jsonObj.put(objName, obj);
		
		response.setContentType(contentType);
		response.setCharacterEncoding(encoding);
		PrintWriter pw = response.getWriter(); 
		pw.write(jsonObj.toString());
		pw.flush();
		
	}
}

action中调用该方法就可以发送json数据了，但是要保证传入的obj是能够序列化的，因此，一般来说需要事先做一些处理，最好的方法当然就是大家都熟悉的bean了：

public class SearchEnToCnAction extends BaseAction {

	// 使用普遍依赖注入方式
	private SearchEnToCnBean searchEnToCnBean;

	@Override
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

                // 取得前台的Ajax数据
		String searchStr = request.getParameter("searchStr");

		List<Object[]> enWordInfo = searchEnToCnBean.searchEnToCn(searchStr);

		if (enWordInfo.isEmpty()) {
			Map<String, Object> jsonResponseLs = new HashMap<String, Object>();
			jsonResponseLs.put("enWordInfo", null);
			
			super.makeJSONObject(response, "enWordResponse", jsonResponseLs);
		} else {
			// json process for EnWord
			List<EnWordVo> jsonEnWordLs = new ArrayList<EnWordVo>();
			EnWordVo jsonEnWord;
			for (int i = 0; i < enWordInfo.size(); i ++) {
				Object[] enWord = enWordInfo.get(i);
				jsonEnWord = new EnWordVo(enWord[0], enWord[1], enWord[2],
						enWord[3], enWord[4], enWord[5], enWord[6], enWord[7],
						enWord[8], enWord[9], enWord[10]);
				jsonEnWordLs.add(jsonEnWord);
			}
			
			// json process for EnExtdWord
			List<Object[]> enExtdWordInfo = searchEnToCnBean.searchEnToCnExtdInfo(searchStr);
			List<EnExtdWordVo> jsonEnExtdWordLs = new ArrayList<EnExtdWordVo>();
			if (enExtdWordInfo.isEmpty()) {
				jsonEnExtdWordLs = null;
			} else {
				EnExtdWordVo jsonEnExtdWord;
				for (int i = 0; i < enExtdWordInfo.size(); i ++) {
					Object[] enExtdWord = enExtdWordInfo.get(i);
					jsonEnExtdWord = new EnExtdWordVo(enExtdWord[0], enExtdWord[1], enExtdWord[2],
							enExtdWord[3], enExtdWord[4], enExtdWord[5], enExtdWord[6], enExtdWord[7],
							enExtdWord[8], enExtdWord[9], enExtdWord[10], enExtdWord[11]);
					jsonEnExtdWordLs.add(jsonEnExtdWord);
				}
			}
			
			Map<String, Object> jsonResponseLs = new HashMap<String, Object>();
			jsonResponseLs.put("enWordInfo", jsonEnWordLs);
			jsonResponseLs.put("enExtdWordInfo", jsonEnExtdWordLs);
			
			super.makeJSONObject(response, "enWordResponse", jsonResponseLs);
		}
		
		return (mapping.findForward(null));
	}

	public void setSearchEnToCnBean(SearchEnToCnBean searchEnToCnBean) {
		this.searchEnToCnBean = searchEnToCnBean;
	}

	public SearchEnToCnBean getSearchEnToCnBean() {
		return searchEnToCnBean;
	}
	
}

上面所使用的两个VO很简单：

public class EnWordVo {

	private Object word;
	private Object extdAttr;
	private Object mean;
	private Object dictId;
	private Object wordId;
	private Object partOfSpeech;
	private Object meaningNum;
	private Object exampleNum;
	private Object exampleExtdAttr;
	private Object enExmp;
	private Object exmpMeaning;
	
	public EnWordVo(Object word, Object extdAttr, Object mean, Object dictId,
			Object wordId, Object partOfSpeech, Object meaningNum,
			Object exampleNum, Object exampleExtdAttr, Object enExmp,
			Object exmpMeaning) {
		super();
		this.word = word;
		this.extdAttr = extdAttr;
		this.mean = mean;
		this.dictId = dictId;
		this.wordId = wordId;
		this.partOfSpeech = partOfSpeech;
		this.meaningNum = meaningNum;
		this.exampleNum = exampleNum;
		this.exampleExtdAttr = exampleExtdAttr;
		this.enExmp = enExmp;
		this.exmpMeaning = exmpMeaning;
	}
	
	public Object getWord() {
		return word;
	}
	public void setWord(String word) {
		this.word = word;
	}
	public Object getExtdAttr() {
		return extdAttr;
	}
	public void setExtdAttr(String extdAttr) {
		this.extdAttr = extdAttr;
	}
	public Object getMean() {
		return mean;
	}
	public void setMean(String mean) {
		this.mean = mean;
	}
	public Object getDictId() {
		return dictId;
	}
	public void setDictId(String dictId) {
		this.dictId = dictId;
	}
	public Object getWordId() {
		return wordId;
	}
	public void setWordId(String wordId) {
		this.wordId = wordId;
	}
	public Object getPartOfSpeech() {
		return partOfSpeech;
	}
	public void setPartOfSpeech(String partOfSpeech) {
		this.partOfSpeech = partOfSpeech;
	}
	public Object getMeaningNum() {
		return meaningNum;
	}
	public void setMeaningNum(String meaningNum) {
		this.meaningNum = meaningNum;
	}
	public Object getExampleNum() {
		return exampleNum;
	}
	public void setExampleNum(String exampleNum) {
		this.exampleNum = exampleNum;
	}
	public Object getExampleExtdAttr() {
		return exampleExtdAttr;
	}
	public void setExampleExtdAttr(String exampleExtdAttr) {
		this.exampleExtdAttr = exampleExtdAttr;
	}
	public Object getEnExmp() {
		return enExmp;
	}
	public void setEnExmp(String enExmp) {
		this.enExmp = enExmp;
	}
	public Object getExmpMeaning() {
		return exmpMeaning;
	}
	public void setExmpMeaning(String exmpMeaning) {
		this.exmpMeaning = exmpMeaning;
	}
}