实体类自动重写toString(),equals()和hashCode()方法

编写web项目时会遇到大量的实体类，那么多的实体类都要重写toString(),equals()和hashCode()方法，造成大量重复代码。

解决方法：

1.编写一个抽象类，在类中重写以上三个方法。

2.让实体类继承这个抽象类。

所用jar包：

apache-commons-lang.jar

例子程序：

Model.java抽象类

package justest;import java.io.Serializable;import org.apache.commons.lang.builder.EqualsBuilder;import org.apache.commons.lang.builder.HashCodeBuilder;import org.apache.commons.lang.builder.ToStringBuilder;import org.apache.commons.lang.builder.ToStringStyle;public abstract class Model implements Serializable {/** *  */private static final long serialVersionUID = 1L;public int hashCode() {return HashCodeBuilder.reflectionHashCode(this);}public String toString() {return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE);}public boolean equals(Object obj) {return EqualsBuilder.reflectionEquals(this, obj);}}

Student.java实体类

package justest;public class Student extends Model {private static final long serialVersionUID = 1L;private Long id;private String name;public Student(Long id, String name) {super();this.id = id;this.name = name;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Long getId() {return id;}}

AutoOverride3Method.java测试类

package justest;public class AutoOverride3Method {public static void main(String[] args) {Student s1 = new Student(1L, "张三");Student s2 = new Student(2L, "李四");Student s3 = new Student(1L, "张三");//测试toString()方法System.out.println(s1);//测试equals方法System.out.println(s1.equals(s2));System.out.println(s1.equals(s3));}}

输出：

Student[id=1,name=张三]falsetrue