grails中執(zhí)行sql操作的代碼很簡單，如下：
def dataSource
def sql = new Sql(dataSource)
def institutionId = 123
def loanFeeSql = "SELECT NVL(SUM(B.LOAN_FEE),0) AS SUM,COUNT(B.ID) AS NUM FROM FUND_ACCOUNT A,LOAN_FEE B,INSTITUTION C "
+"WHERE A.INSTITUTION_ID = C.ID AND C.ID =? AND A.BANK_ACCOUNT = B.REMIT_BANK_ACCOUNT"
def loanFeeList = sql.rows(loanFeeSql,institutionId)
本來不會覺得有任何問題，但執(zhí)行之后卻發(fā)生異常：
No signature of method: java.lang.String.positive() is applicable for argument types: () values: []
Possible solutions: notify(), size(), size(), tokenize(), tokenize(). Stacktrace follows:
groovy.lang.MissingMethodException: No signature of method: java.lang.String.positive() is applicable for argument types: () values: []
Possible solutions: notify(), size(), size(), tokenize(), tokenize()
這個異常還真是百思不得其解啊，和java.lang.String.positive()有什么關(guān)系呢，百度之，查了好久，又問了我的一個同事，才發(fā)現(xiàn)，groovy中因?yàn)闆]有分號作為每一行的分隔符，所以，如果一個字符串需要使用“+”拼起來，則需要把“+”寫在上一行的末尾，如果寫到下一行的開頭，則可能默認(rèn)下一行是另外一條語句，暈。。。
所以，正確的寫法是：
def loanFeeSql = "SELECT NVL(SUM(B.LOAN_FEE),0) AS SUM,COUNT(B.ID) AS NUM FROM FUND_ACCOUNT A,LOAN_FEE B,INSTITUTION C "+
"WHERE A.INSTITUTION_ID = C.ID AND C.ID =? AND A.BANK_ACCOUNT = B.REMIT_BANK_ACCOUNT"
或者使用三個分號，這樣編譯器會將上下兩行自動識別為一個字符串：
def loanFeeSql = """SELECT NVL(SUM(B.LOAN_FEE),0) AS SUM,COUNT(B.ID) AS NUM FROM FUND_ACCOUNT A,LOAN_FEE B,INSTITUTION C
WHERE A.INSTITUTION_ID = C.ID AND C.ID =? AND A.BANK_ACCOUNT = B.REMIT_BANK_ACCOUNT"""
參考資料：http://heqiang421.blog.163.com/blog/static/232275071201472924551504/