JDBC PreparedStatement Like参数报错解决方案
cuisuqiang 人气:0由于我们的项目不大,所以刚开始决定时我为了省事想用SSH,可是后来觉得只有Struts2好了,后来的查询等数据库操作我自己写方法不行了嘛!
刚才写一个公共查询的方法,在增加参数时出了点错误,就是使用模糊查询时犯晕了。
我写的方法如下:
/** * @说明 执行一条查询SQL语句,可以带参数 */ public static List<Object[]> excuteQuery(String sql, Object[] objs) { Connection conn = null; PreparedStatement psta = null; ResultSet rs = null; List<Object[]> iResult = null; Object[] objArr = null; try { conn = getConn(); // 得到链接 PreparedStatement state = conn.prepareStatement(sql); if(null != objs){ for (int i = 0; i < objs.length; i++) { state.setObject(i + 1, objs[i]); } } ResultSet resultSet = state.executeQuery(); // 执行查询,返回结果接集合 iResult = new ArrayList<Object[]>(); int count = resultSet.getMetaData().getColumnCount(); // 一共有多少列数据 while (resultSet.next()) { objArr = new Object[count]; for (int i = 1; i <= count; i++) { objArr[i - 1] = resultSet.getObject(i); // 增加到返回的集合中 } iResult.add(objArr); } } catch (Exception e) { e.printStackTrace(); iResult = null; } finally { try { if (rs != null) { rs.close(); } if (psta != null) { psta.close(); } if (conn != null) { conn.close(); } } catch (Exception e2) { } } return iResult; }
后来我输入这样的一个参数进行查询:
public static void main(String[] args) { Object[] para = new Object[]{"c"}; List<Object[]> list = excuteQuery("select * from s_user t where t.userName like '%?%'",para); for (Object[] o : list) { for (Object ob : o) { System.out.print(ob + "-"); } System.out.println(); } }
结果报错如下:
java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0). at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1056) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927) at com.mysql.jdbc.PreparedStatement.checkBounds(PreparedStatement.java:3279) at com.mysql.jdbc.PreparedStatement.setInternal(PreparedStatement.java:3263) at com.mysql.jdbc.PreparedStatement.setString(PreparedStatement.java:4087) at com.mysql.jdbc.PreparedStatement.setObject(PreparedStatement.java:3513) at org.apache.commons.dbcp.DelegatingPreparedStatement.setObject(DelegatingPreparedStatement.java:166) at com.nms.common.db.ConnectionManager.excuteQuery(ConnectionManager.java:86) at com.nms.common.db.ConnectionManager.main(ConnectionManager.java:20) Exception in thread "main" java.lang.NullPointerException at com.nms.common.db.ConnectionManager.main(ConnectionManager.java:21)
后来才知道,模糊查询时要这样写:
public static void main(String[] args) { Object[] para = new Object[]{"%c%"}; List<Object[]> list = excuteQuery("select * from s_user t where t.userName like ?",para); for (Object[] o : list) { for (Object ob : o) { System.out.print(ob + "-"); } System.out.println(); } }
就这么简单,闲话不说了!
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