postgresql - 使用 Postgres 配置 Tomcat 8

Question

我想用 PostgreSQL 配置 Tomcat 8

我在 context.xml 中添加了这个

<Resource name="jdbc/DefaultDB" auth="Container" type="javax.sql.DataSource"
          username="postgres" password="qwerty"
          url="jdbc:postgresql://localhost:5432/crm"
          driverClassName="org.postgresql.Driver"
          initialSize="5" maxWait="5000"
          maxActive="120" maxIdle="5"
          validationQuery="select 1"
          poolPreparedStatements="true"/>

然后我尝试运行这段 Java 代码:

public String init()
    {
        String user_name = null;
        try
        {
            Context ctx = new InitialContext();
            if (ctx == null)
                throw new Exception("Boom - No Context");

            DataSource ds = (DataSource) ctx.lookup("jdbc/DefaultDB");

            if (ds != null)
            {
                Connection conn = ds.getConnection();

                if (conn != null)
                {
                    Statement stmt = conn.createStatement();
                    ResultSet rst = stmt.executeQuery("select id, user_name from user where username = " + user);
                    if (rst.next())
                    {
                        user_name = rst.getString("user_name");
                    }
                    conn.close();
                }
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

        return user_name;
    }

但由于某种原因，在我添加此代码后，Tomcat 没有启动。你知道我哪里错了吗？

我在 Tomcat 日志文件中得到这个:

    28-Mar-2016 10:37:07.955 WARNING [localhost-startStop-1] org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory.getObjectInstance Name = DefaultDB Property maxActive is not used in DBCP2, use maxTotal instead. maxTotal default value is 8. You have set value of "120" for "maxActive" property, which is being ignored.
    28-Mar-2016 10:37:07.956 WARNING [localhost-startStop-1] org.apache.tomcat.dbcp.dbcp2.BasicDataSourceFactory.getObjectInstance Name = DefaultDB Property maxWait is not used in DBCP2 , use maxWaitMillis instead. maxWaitMillis default value is -1. You have set value of "5000" for "maxWait" property, which is being ignored.

javax.naming.NameNotFoundException: Name [jdbc/DefaultDB] is not bound in this Context. Unable to find [jdbc].

Answer 1

正如@a_horse_with_no_name 所说，您的查询是错误的。你的代码必须是这样的:

public String init()
{
    String user_name = null;
    try
    {
        Context ctx = new InitialContext();
        if (ctx == null)
            throw new Exception("Boom - No Context");
        Context envCtx = (Context) ctx.lookup("java:comp/env");
        DataSource ds = (DataSource) envCtx.lookup("jdbc/DefaultDB");

        if (ds != null)
        {
            Connection conn = ds.getConnection();

            if (conn != null)
            {
                Statement stmt = conn.createStatement();
                ResultSet rst = stmt.executeQuery("select id, user_name from user where username = " + user);
                if (rst.next())
                {
                    user_name = rst.getString("user_name");
                }
                conn.close();
            }
        }
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }

    return user_name;
}