java中的Mysql查询
我有一个来自netbeans中生成的数据库的服务rest。这将为每个表创建实体类
@Entity
@Table(name = "users")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Users.findAll",
query = "SELECT u FROM Users u"),
@NamedQuery(name = "Users.findById",
query = "SELECT u FROM Users u WHERE u.id = :id"),
@NamedQuery(name = "Users.findByName",
query = "SELECT u FROM Users u WHERE u.name = :name"),
@NamedQuery(name = "Users.findByTelephone",
query = "SELECT u FROM Users u WHERE u.telephone = :telephone"),
@NamedQuery(name = "Users.findByYear",
query = "SELECT u FROM Users u WHERE u.year = :year")})
public class Users implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@Basic(optional = false)
@NotNull
@Column(name = "id")
private Integer id;
@Size(max = 25)
@Column(name = "name")
private String name;
@Column(name = "telephone")
private Integer telephone;
@Column(name = "year")
private Integer year;
public Users() {
}
public Users(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getTelephone() {
return telephone;
}
public void setTelephone(Integer telephone) {
this.telephone = telephone;
}
public Integer getYear() {
return year;
}
public void setYear(Integer year) {
this.year = year;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Users)) {
return false;
}
Users other = (Users) object;
if ((this.id == null && other.id != null)
|| (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "glee.Users[ id=" + id + " ]";
}
我如何从另一个类查询这个类的数据库?
例如,执行选择:从bb中选择name
。用户;
并将其保存在数组中
谢谢
# 1 楼答案
这两种方法都将检索查询,并且您可以使用基本查询操作执行查询