package org.hibernate.test;public class T1 {
private int id;
private T2 t2;
public T1() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public T2 getT2() {
return t2;
}
public void setT2(T2 t2) {
this.t2 = t2;
}
public void test() {
T1 t1 = new T1();
t1.getT2().setId(110);
}
public static void main(String[] args) {
T1 t1 = new T1();
t1.test();
}
}package org.hibernate.test;public class T2 {
private int id; public T2() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public static void main(String[] args) {
T2 t2 = new T2();
System.out.println(t2.getId());
}
}
执行T1的时候后台报了这个错
<many-to-one name="holiday" class="com.basedatas.workday.db.Holiday" fetch="select" lazy="false">
<column name="HOLIDAYID" not-null="true" />
</many-to-one>
类似以上,具体你查一下hibernate相关文档关于联查的内容。
package org.hibernate.test;public class T1 {
private int id;
private T2 t2;
public T1() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public T2 getT2() {
return t2;
}
public void setT2(T2 t2) {
this.t2 = t2;
}
public void test() {
T1 t1 = new T1();
t1.setT2(t2);// <----------------------------------------------------添加了这句,不知道是不是这个意思
t1.getT2().setId(110);
}
public static void main(String[] args) {
T1 t1 = new T1();
t1.test();
}
}依然报的空指针错误……
package org.hibernate.test;public class T1 {
private int id;
private T2 t2;
public T1() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public T2 getT2() {
return t2;
}
public void setT2(T2 t2) {
this.t2 = t2;
}
public static void main(String[] args) {
T1 t1 = new T1();
t1.setT2(new T2());//<---------------------------------我删除了test方法,然后改成这样,是这个意思吗?
t1.getT2().setId(110);
}
}
private int id;
private T2 t2;
public T1() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public T2 getT2() {
return t2;
}
public void setT2(T2 t2) {
this.t2 = t2;
}
public void test() {
T1 t1 = new T1();
t1.setT2(new T2());
t1.getT2().setId(110);
System.out.println( t1.getT2().getId());
}
public static void main(String[] args) {
T1 t1 = new T1();
t1.test();
}
}这样就可以了
T2类就是这个:package org.hibernate.test;public class T2 { /**
* @param args
*/
private int id; public T2() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
T2 t2 = new T2();
System.out.println(t2.getId());
}
}
package com.snail.test;public class T1 {
private int id;
private T2 t2;
public T1() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public T2 getT2() {
return t2;
}
public void setT2(T2 t2) {
this.t2 = t2;
}
public void test() {
this.getT2().setId(110);
}
}
package com.snail.test;public class T2 {
private int id; public T2() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}package com.snail.test;public class Test { public static void main(String[] args) {
T1 t1 = new T1();
T2 t2 = new T2();
t1.setT2(t2);
t1.test();
System.out.println(t2.getId());
}}