JDBC批量更新。

数据量大时处理。

// 生成自测成绩 lizhuang 2012年8月6日@SuppressWarnings("unchecked")public String makeTestScore() {dbpool pool = new dbpool();Connection conn = pool.getConn();Statement ps = null;try {ps = conn.createStatement();for (int j = 0; j < stuList.size(); j++) {String sql = "UPDATE pe_bzz_examscore t  SET t.test_score=IFNULL((select round(s.AVG_test_score,1) from stat_study_summary s" + " where s.student_id=0;";ps.addBatch(sql);if (StringUtils.isNotBlank(stuList.get(j).getTotal_score())) {Double total_score = (Double.parseDouble(exam_score) * exam_scale + Double.parseDouble(test_score) * test_scale) / 100;String totalScore = df.format(total_score);sql = "update pe_bzz_examscore t set t.total_score=" + totalScore + " where t.id='" + stuList.get(j).getId() + "';";ps.addBatch(sql);}// 如果考核等级不为空，同步更新if (StringUtils.isNotBlank(stuList.get(j).getTotal_grade())) {String grade = null;Double total_score = Double.parseDouble(stuList.get(j).getTotal_score());if (total_score < 60) {grade = "不及格";} else if (total_score >= 60 && total_score < 75) {grade = "合格";} else if (total_score >= 75 && total_score < 90) {grade = "良好";} else if (total_score >= 90) {grade = "优秀";}sql = "update pe_bzz_examscore t set t.total_grade='" + grade + "'where t.id='" + stuList.get(j).getId() + "';";ps.addBatch(sql);}if (j == stuList.size() - 1) {// 如果到达末尾，全部提交ps.executeBatch();break;}if (j % 200 == 0 && j != 0) {// 每200条批量提交一次ps.executeBatch();}}ps.close();conn.close();} catch (Exception e1) {e1.printStackTrace();request().setAttribute("msg", "生成失败。");return "extmsg";}request().setAttribute("msg", "全部生成成功！");// request().setAttribute("url",// "/entity/exam/peBzzExamScore.action?tag=search");return "extmsg";}

就是一个addBatch和executeBatch何时提交的问题。记录一下。

addBatch