我使用spring jdbc模板从oracle数据库中检索400条记录。 之后我使用行映射器将行转换为对象。对象中的某些值没有任何值。当我在pl / sql编辑器中测试相同的sql时，我能够看到行的所有行和所有列。当我调试应用程序时，我收到以下错误。如果我为同一个查询获取较少数量的记录（7），它工作正常。行映射器正在设置对象的所有值。你能帮我解决这个问题。
java.sql.SQLException: statement handle not executed
2017-02-09 15:45:39 INFO XmlBeanDefinitionReader:317 - Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml]
2017-02-09 15:45:39 INFO SQLErrorCodesFactory:126 - SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase, Hana]
2017-02-09 15:45:39 WARN SQLErrorCodesFactory:227 - Error while extracting database product name - falling back to empty error codes
org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is java.sql.SQLException: Connection has already been closed.
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:305)
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:329)
at org.springframework.jdbc.support.SQLErrorCodesFactory.getErrorCodes(SQLErrorCodesFactory.java:214)
at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.setDataSource(SQLErrorCodeSQLExceptionTranslator.java:134)
at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.<init>(SQLErrorCodeSQLExceptionTranslator.java:97)
at org.springframework.jdbc.support.JdbcAccessor.getExceptionTranslator(JdbcAccessor.java:99)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:645)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:680)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:707)
at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:757)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:192)
答案 0 :(得分：0)
如果从数据库中检索这400行需要一些时间，我假设您正在达到数据库连接超时。如果是，请在使用资源池时增加using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ShopEntity
{
class Product
{
public int ProductId { get; set; }
public int Price { get; set; }
public string ProductName { get; set; }
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ShopEntity
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
using (var ctx = new ShopContext())
{
User adminUser = new User()
{
Address = "Skejby Vænge 96A",
EMailAddress = "anderskloborg@gmail.com",
IsAdmin = 1,
PassWord = "12345678",
UserName = "Anders1234"
};
//Product Apple = new Product() { Price = 2, ProductName = "Apple" };
//Product Melon = new Product() { Price = 10, ProductName = "Melon" };
//Product Beef = new Product() { Price = 40, ProductName = "Beef" };
ctx.Users.Add(adminUser);
//ctx.Products.Add(Apple);
//ctx.Products.Add(Melon);
//ctx.Products.Add(Beef);
ctx.SaveChanges();
}
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
}
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ShopEntity
{
class ShopContext: DbContext
{
public ShopContext() : base()
{
}
public DbSet<User> Users { get; set; }
public DbSet<Product> Products { get; set; }
}
}
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ShopEntity
{
class User
{
public int UserId { get; set; }
[MaxLength(20)]
public string UserName { get; set; }
[MaxLength(20)]
public string PassWord { get; set; }
public string EMailAddress { get; set; }
[MaxLength(50)]
public string Address { get; set; }
public byte IsAdmin { get; set; }
}
}
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
</configuration>
。调试代码时也可能发生超时。
也可能是数据库端的超时。在这种情况下，您必须调整数据库超时参数。