FactoryBean接口的使用

一般情況下，Spring通過反射機制利用bean的class屬性指定實現類來實例化bean。在某些情況下，實例化bean過程比較複雜，如果按照傳統的方式，則需要在標籤中提供大量的配置信息，配置方式的靈活性是受限的。爲此，spring可以通過實現FactoryBean的接口來定製實例化bean的邏輯。
1 創建User對象

package com.gientech.factoryBean;



public class User {

    private String id;

    private String userName;

    private String email;

    private String password;

    public User(String userName) {
        this.userName = userName;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

2 創建MyFactoryBean

package com.gientech.factoryBean;


import org.springframework.beans.factory.FactoryBean;

public class MyFactoryBean implements FactoryBean<User> {
    @Override
    public User getObject() throws Exception {
        return new User("wangmazi");
    }

    @Override
    public Class<?> getObjectType() {
        return User.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }
}

3 修改xml配置文件