java代码中执行sql报错：java.sql.SQLException: ORA-00923: 未找到要求的 FROM 关键字

最近写了特别多的数据库同步接口，需要在java程序中拼接大段的sql，然后再提交执行，出现了很多次ORA-00923错误，都有点见怪不怪了。

比如下面这段代码，在执行 db.execute(insertSql) 时肯定会报这个错误的。

@Override
public int doInsert(DB db,InterfaceLogBean logBean) {
	StringBuilder insertBuilder = new StringBuilder();
	insertBuilder.append("INSERT INTO ");
	insertBuilder.append("MTL_ONHAND_QUANTITIES_DETAIL ");
	insertBuilder.append("(INVENTORY_ITEM_ID,ITEM_CODE,ORGANIZATION_ID,DATE_RECEIVED,LAST_UPDATE_DATE,LAST_UPDATED_BY,CREATION_DATE,CREATED_BY,");
	insertBuilder.append("PRIMARY_TRANSACTION_QUANTITY,SUBINVENTORY_CODE,LOT_NUMBER,ONHAND_QUANTITIES_ID,ORGANIZATION_TYPE,");
	insertBuilder.append(" OWNING_ORGANIZATION_ID,TRANSACTION_UOM_CODE,TRANSACTION_QUANTITY,IS_CONSIGNED)");
	insertBuilder.append("SELECT INVENTORY_ITEM_ID,ITEM_CODE,84,DATE_RECEIVED,LAST_UPDATE_DATE,LAST_UPDATED_BY,CREATION_DATE,CREATED_BY, ");	
	insertBuilder.append("PRIMARY_TRANSACTION_QUANTITY,SUBINVENTORY_CODE,LOT_NUMBER,ONHAND_QUANTITIES_ID,ORGANIZATION_TYPE,");
	insertBuilder.append("OWNING_ORGANIZATION_ID,TRANSACTION_UOM_CODE,TRANSACTION_QUANTITY,IS_CONSIGNED");
	insertBuilder.append("FROM MTL_ONHAND_QUANTITIES_TEMP MOQT ");
	insertBuilder.append("WHERE 1=1 AND NOT EXISTS(SELECT 1 FROM MTL_ONHAND_QUANTITIES_DETAIL MOQD WHERE 1=1 AND MOQD.ONHAND_QUANTITIES_ID = MOQT.ONHAND_QUANTITIES_ID)");
	String insertSql = insertBuilder.toString();
	insertBuilder.delete(0, insertBuilder.length());
	try {
			return db.execute(insertSql);
		} catch (JDBCException e) {
			e.printStackTrace();
			logBean.setExceptContent(e.getMessage());
			return -1;
		} catch (Exception e) {
			e.printStackTrace();
			logBean.setExceptContent(e.getMessage());
			return -1;
		}
	}

你如果有时间的话，可以DEBUG一下，在insertSql执行前这段sql是啥，再复制到plsql中执行一下你就知道问题出在哪儿了。
原因很简单，就是sql在拼接的时候，该有空格或者换行的地方没有，倒数第是哪个append后面需要留一个空格出来，这样后面的IS_CONSIGNED就不会和后面的FROM拼在一起，如果没有这个空格，insertSql中就会出现IS_CONSIGNEDFROM，自然而然找不到FROM关键字了。
还有另一个方法就是在每段待拼接的字符串后面加上"\n"这样拼接的字符串格式就会每段换行。

• 示例一

	public static void main(String[] args) {
		StringBuilder stringBuilder = new StringBuilder();
		stringBuilder.append("SELECT ID,NAME,AGE");
		stringBuilder.append("FROM STUDENT");
		System.out.println(stringBuilder.toString());
		//输出内容为：SELECT ID,NAME,AGEFROM STUDENT
		//会报错ORA-00923
	}

• 示例二

	public static void main(String[] args) {
		StringBuilder stringBuilder = new StringBuilder();
		stringBuilder.append("SELECT ID,NAME,AGE\n");
		stringBuilder.append("FROM STUDENT\n");
		System.out.println(stringBuilder.toString());
		/**
		符合要求
		输出内容为：
		SELECT ID,NAME,AGE
		FROM STUDENT		
		*/
	}

• 实例三

	public static void main(String[] args) {
		StringBuilder stringBuilder = new StringBuilder();
		stringBuilder.append("SELECT ID,NAME,AGE ");
		stringBuilder.append("FROM STUDENT");
		System.out.println(stringBuilder.toString());
		/**
		符合要求
		输出内容为：
		SELECT ID,NAME,AGE FROM STUDENT
		*/
	}