1、替换bean对象中的方法：
(1)原始bean对象MyValueCalculator中的方法computeValue。

package com.it.app.demo;

public class MyValueCalculator {
    
    public String computeValue(String input) {
        return input;
    }
}

(2)bean对象ReplacementComputeValue的方法(reimplement)去替换。

package com.it.app.demo;

import org.springframework.beans.factory.support.MethodReplacer;

import java.lang.reflect.Method;

public class ReplacementComputeValue implements MethodReplacer {

    public Object reimplement(Object o, Method m, Object[] args) throws Throwable {
        String input = (String) args[0];
        return input.substring(0,3);
    }
}

(3)xml对象放到spring容器中配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="myValueCalculator" class="com.it.app.demo.MyValueCalculator">
        <replaced-method name="computeValue" replacer="replacementComputeValue">
            <arg-type>Str</arg-type>
        </replaced-method>
    </bean>
    <bean id="replacementComputeValue" class="com.it.app.demo.ReplacementComputeValue"></bean>
</beans>

(4)执行测试类：

package com.it.app;

import com.it.app.demo.MyValueCalculator;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppFive {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-contextFour.xml");
        MyValueCalculator myValueCalculator = (MyValueCalculator) context.getBean("myValueCalculator");
        System.out.println(myValueCalculator.computeValue("abcdef"));
        
    }
}

(5)执行结果：为abc 替换input输入的abcdef

abc