java - 将java.sql.Connection转换为PGConnection

我想用Tomcat在PostgreSQL中上传一个文件：

@Resource(name = "jdbc/DefaultDB")
private DataSource ds;
Connection conn = ds.getConnection();

我试着用这种方式投射conn对象：

PGConnection pgCon = ((org.apache.commons.dbcp.DelegatingConnection) conn).getInnermostDelegate();

我明白了

Caused by: java.lang.ClassCastException: org.apache.tomcat.dbcp.dbcp2.PoolingDataSource$PoolGuardConnectionWrapper cannot be cast to org.postgresql.PGConnection

我也试过：

Connection unwrap = conn.unwrap(Connection.class);
connSec = (org.postgresql.PGConnection) unwrap;

我明白了

java.sql.SQLException: Cannot unwrap to org.postgresql.PGConnection

LargeObjectManager pgCon = pgCon.getLargeObjectAPI();

实现代码的正确方法是什么？
附笔
我试过这个：

PGConnection pgConnection = null;

if (conn.isWrapperFor(PGConnection.class))
{
    pgConnection = conn.unwrap(PGConnection.class);
}

LargeObjectManager lobj = pgConnection.getLargeObjectAPI();

但我在这一行得到NPELargeObjectManager lobj = pgConnection.getLargeObjectAPI();

最佳答案

if (dataSource.getConnection().isWrapperFor(PGConnection.class)) {
  PGConnection pgConnection = dataSource.getConnection().unwrap(PGConnection.class);
}

关于java - 将java.sql.Connection转换为PGConnection，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36986653/