在mysql查询中传递java字符串变量

使用

PreparedStatement

String

final String sql = "select * from production AS cust INNER JOIN location"    + " AS comp ON cust.location_id = comp.location_id where "    + "comp.name = ? AND crop_id = 1";PreparedStatement ps = null;try {  ps = conn.prepareStatement(sql);  ps.setString(1, "taplejung");} catch (Exception e) {  e.printStackTrace();} finally {  if (ps != null) {    try {      ps.close();    } catch (Exception ignored) {    }  }}

编辑 （根据您的其他代码，将其更改为类似内容）

PreparedStatement ps = null;String sql = null;if (cropnames.equals("paddy")) {  // System.out.println();  sql = "SELECt * FROM `production` AS cust INNER JOIN location AS comp "      + "ON cust.location_id = comp.location_id WHERe comp.name = "      + "? AND crop_id = 1";} else {  sql = "SELECt * FROM `production` WHERe crop_id = 4 AND location_id = 10";}ps = conn.prepareStatement(sql);if (cropnames.equals("paddy")) {  ps.setString(1, locationnames);}System.out.println(sql);ResultSet rs = ps.executeQuery();