Freemarker输出字符串而不是文件
??? Freemarker一般是通过writer输出到文件的处理过程，但是这个过程不是很优化的，大量的IO操作使程序变的很慢。尤其是生成对应的文件后，再做一些处理，更是慢上加慢。
??? 废话少说，先看看改造前的代码。
cfg.setClassForTemplateLoading(this.getClass(), "/");cfg.setObjectWrapper(new DefaultObjectWrapper());cfg.setNumberFormat("################");Questionnaire questionnaire = questionnaireDAO.findById(input.getDialogId());Map root = new HashMap();root.put("questionnaire", questionnaire);Template template = cfg.getTemplate("soapRequest.ftl");OutputStream os = conn.getOutputStream();Writer out = new BufferedWriter(new OutputStreamWriter(os, "utf-8"));template.process(root, out);out.flush();out.close();?修改后的。
cfg.setClassForTemplateLoading(this.getClass(), "/");cfg.setObjectWrapper(new DefaultObjectWrapper());cfg.setNumberFormat("################");Questionnaire questionnaire = questionnaireDAO.findById(input.getDialogId());Map root = new HashMap();root.put("questionnaire", questionnaire);/*** StringWriter instead of Writer* Class StringWriter contains a StringBuffer which can be rendered toString* modify by heweiya*/StringWriter stringWriter = new StringWriter();BufferedWriter writer = new BufferedWriter(stringWriter);template.setEncoding("UTF-8");template.process(root, writer);StringReader reader = new StringReader(stringWriter.toString());writer.flush();writer.close();?说白了就是使用StringWriter代替了writer,我在代码里直接转换成了StringReader，同样，如果你没有必要做这个的话，你可以把StringWriter转换成String.
Configuration cfg = new Configuration();cfg.setDefaultEncoding(encoding);Template t = new Template(TEMPALTE_DEFAULT_KEY, new StringReader(templateStr), cfg);StringWriter out = new StringWriter();t.process(map, out);return out.getBuffer().toString();Configuration cfg = new Configuration();cfg.setDefaultEncoding(encoding);Template t = new Template(TEMPALTE_DEFAULT_KEY, new StringReader(templateStr), cfg);StringWriter out = new StringWriter();t.process(map, out);return out.getBuffer().toString();