在mysql中返回null而不是列值

Question

我在Java EE应用程序中从数据库获取数据。

WdLeavesSupplier supplier = entityManager.getEntityManager()
        .find(WdLeavesSupplier.class,
                Integer.parseInt(supplier_id));

此实体中有一列active。我已在此处插入了一些数据，这些记录中active列的值为on。当我如上所述检索数据时，我的null列的值为active。其他列（名称，地址等）值正确。

这样的数据库记录。

supplier_id, supplier_code, supplier_first_name, supplier_last_name, supplier_phone, supplier_address_a, supplier_address_b, center_id, active, comment, created_date
14, 't1', 'Mark', 'Smith', '0711234224', 'g45, new town', 'Galle', 41, 'on', 'test comment', '2014-06-24 17:06:38'

这是表结构。

CREATE TABLE  `wdtccdb`.`wd_leaves_supplier` (
  `supplier_id` int(10) unsigned NOT NULL auto_increment,
  `supplier_code` varchar(45) NOT NULL default '',
  `supplier_first_name` varchar(45) NOT NULL default '',
  `supplier_last_name` varchar(45) default NULL,
  `supplier_phone` varchar(45) default NULL,
  `supplier_address_a` varchar(45) default NULL,
  `supplier_address_b` varchar(45) default NULL,
  `center_id` int(10) unsigned NOT NULL default '0',
  `active` varchar(5) default NULL,
  `comment` varchar(100) default NULL,
  `created_date` timestamp NOT NULL default CURRENT_TIMESTAMP,
  PRIMARY KEY  (`supplier_id`),
  UNIQUE KEY `supp_code_un` (`supplier_code`),
  KEY `FK_wd_leaves_supplier_center_id` (`center_id`),
  CONSTRAINT `FK_wd_leaves_supplier_center_id` FOREIGN KEY (`center_id`) REFERENCES `wd_collection_center` (`center_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

实体类Link

实体类代码

package com.wd.entity;

import java.io.Serializable;
import javax.persistence.*;
import java.sql.Timestamp;
import java.util.List;

/**
 * The persistent class for the wd_leaves_supplier database table.
 * 
 */
@Entity
@Table(name = "wd_leaves_supplier")
@NamedQueries({
        @NamedQuery(name = "WdLeavesSupplier.findAll", query = "SELECT u FROM WdLeavesSupplier u"),
        @NamedQuery(name = "WdLeavesSupplier.findByCode", query = "SELECT u FROM WdLeavesSupplier u WHERE u.supplierCode = :code") })
public class WdLeavesSupplier implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "supplier_id")
    private int supplierId;

    private String active;

    private String comment;

    @Column(name = "created_date")
    private Timestamp createdDate;

    @Column(name = "supplier_address_a")
    private String supplierAddressA;

    @Column(name = "supplier_address_b")
    private String supplierAddressB;

    @Column(name = "supplier_code")
    private String supplierCode;

    @Column(name = "supplier_first_name")
    private String supplierFirstName;

    @Column(name = "supplier_last_name")
    private String supplierLastName;

    @Column(name = "supplier_phone")
    private String supplierPhone;

    // bi-directional many-to-one association to WdLeafPurchase
    @OneToMany(mappedBy = "wdLeavesSupplier")
    private List<WdLeafPurchase> wdLeafPurchases;

    // bi-directional many-to-one association to WdCollectionCenter
    @ManyToOne
    @JoinColumn(name = "center_id")
    private WdCollectionCenter wdCollectionCenter;

    // bi-directional many-to-one association to WdSupplierLoan
    @OneToMany(mappedBy = "wdLeavesSupplier")
    private List<WdSupplierLoan> wdSupplierLoans;

    public WdLeavesSupplier() {
    }

    public int getSupplierId() {
        return this.supplierId;
    }

    public void setSupplierId(int supplierId) {
        this.supplierId = supplierId;
    }

    public String getActive() {
        return this.active;
    }

    public void setActive(String active) {
        this.active = active;
    }

    public String getComment() {
        return this.comment;
    }

    public void setComment(String comment) {
        this.comment = comment;
    }

    public Timestamp getCreatedDate() {
        return this.createdDate;
    }

    public void setCreatedDate(Timestamp createdDate) {
        this.createdDate = createdDate;
    }

    public String getSupplierAddressA() {
        return this.supplierAddressA;
    }

    public void setSupplierAddressA(String supplierAddressA) {
        this.supplierAddressA = supplierAddressA;
    }

    public String getSupplierAddressB() {
        return this.supplierAddressB;
    }

    public void setSupplierAddressB(String supplierAddressB) {
        this.supplierAddressB = supplierAddressB;
    }

    public String getSupplierCode() {
        return this.supplierCode;
    }

    public void setSupplierCode(String supplierCode) {
        this.supplierCode = supplierCode;
    }

    public String getSupplierFirstName() {
        return this.supplierFirstName;
    }

    public void setSupplierFirstName(String supplierFirstName) {
        this.supplierFirstName = supplierFirstName;
    }

    public String getSupplierLastName() {
        return this.supplierLastName;
    }

    public void setSupplierLastName(String supplierLastName) {
        this.supplierLastName = supplierLastName;
    }

    public String getSupplierPhone() {
        return this.supplierPhone;
    }

    public void setSupplierPhone(String supplierPhone) {
        this.supplierPhone = supplierPhone;
    }

    public List<WdLeafPurchase> getWdLeafPurchases() {
        return this.wdLeafPurchases;
    }

    public void setWdLeafPurchases(List<WdLeafPurchase> wdLeafPurchases) {
        this.wdLeafPurchases = wdLeafPurchases;
    }

    public WdCollectionCenter getWdCollectionCenter() {
        return this.wdCollectionCenter;
    }

    public void setWdCollectionCenter(WdCollectionCenter wdCollectionCenter) {
        this.wdCollectionCenter = wdCollectionCenter;
    }

    public List<WdSupplierLoan> getWdSupplierLoans() {
        return this.wdSupplierLoans;
    }

    public void setWdSupplierLoans(List<WdSupplierLoan> wdSupplierLoans) {
        this.wdSupplierLoans = wdSupplierLoans;
    }

}

如何解决此错误？