spring set注入

上篇文章说到了构造器注入。可是有时候构造器注入并非非常好用，如今来看下set注入。

构造器注入博客地址：http://blog.csdn.net/luckey_zh/article/details/46671307

看下样例：

public class Roles {
	private int id;
	private String roleName;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getRoleName() {
		return roleName;
	}
	public void setRoleName(String roleName) {
		this.roleName = roleName;
	}
	//重写toString方法。方便測试
	@Override
	public String toString() {
		return "Roles [id=" + id + ", roleName=" + roleName + "]";
	}
}

spring配置：

	<bean id="roles" class="cn.com.ztz.spring.model.Roles">
		<property name="id" value="2"/>
		<property name="roleName" value="管理员"/>
	</bean>

測试main方法:

public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
		Roles r=(Roles)context.getBean("roles");
		System.out.println(r.toString());
	}

输出结果:

Roles [id=2, roleName=管理员]

看spring配置。我们能发现构造器<constructor-arg/> set注入是<property/> 

一个bean引用其它的bean也是几乎相同的。看下样例

public class Roles {
	private int id;
	private String roleName;
	private Users users;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getRoleName() {
		return roleName;
	}
	public void setRoleName(String roleName) {
		this.roleName = roleName;
	}
	public void setUsers(Users users) {
		this.users = users;
	}
	public Users getUsers() {
		return users;
	}
	//重写toString方法，方便測试
	@Override
	public String toString() {
		return "Roles [id=" + id + ", roleName=" + roleName + ", users="
				+ users + "]";
	}
}

public class Users {
	private int id;
	private String name;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Users [id=" + id + ", name=" + name + "]";
	}
}

spring配置：

<bean id="roles" class="cn.com.ztz.spring.model.Roles">
		<property name="id" value="2"/>
		<property name="roleName" value="管理员"/>
		<property name="users" ref="users"/>
	</bean>
	
	<bean id="users" class="cn.com.ztz.spring.model.Users">
		<property name="id" value="2"/>
		<property name="name" value="张三"/>
	</bean>

执行以上測试方法输出结果：

Roles [id=2, roleName=管理员, users=Users [id=2, name=张三]]