反射构建对象

Constructor<?> java.lang.Class<?>... parameterTypes)

jdk1.5后用...三个点代表可变参数（可看成动态数据，动态接受不同的数据，但是类型要是相同的），可以不填

package utils;
/**
 * 模拟数据源对象
 * @author Administrator
 *javax.sql.DataSource
 *模拟写一个开源的连接池
 *如何将此对象交给Spring管理
 *1)以xml的方式对此对象进行描述(在配置文件中以<bean>标签描述)
 *2)以注解的方式对此对象进行描述
 */
public class OpenDataSource {
    private String driverClassName;
    private String url;
    private String userName;
    private String password;
    private Integer coreSize;
    private Integer maxSize;
    public OpenDataSource() {
        System.out.println("OpenDataSource.OpenDataSource()-0");
    }
    public OpenDataSource(int coreSize){
        System.out.println("OpenDataSource.OpenDataSource()-1");
        this.coreSize=coreSize;
    }
    //为属性赋值的过程叫值的注入，也叫依赖注入，通过调用对象的set方法赋值
    public OpenDataSource(int coreSize,int maxSize) {
        System.out.println("OpenDataSource.OpenDataSource()-2");
        this.coreSize=coreSize;
        this.maxSize=maxSize;
    }
    
    public Integer getCoreSize() {
        return coreSize;
    }

    public void setCoreSize(Integer coreSize) {
        this.coreSize = coreSize;
    }

    public Integer getMaxSize() {
        return maxSize;
    }

    public void setMaxSize(Integer maxSize) {
        this.maxSize = maxSize;
    }

    public void init(){
        System.out.println("OpenDataSource.init()");
    }
    public void close(){
        System.out.println("OpenDataSource.destory()");
    }
    
    public String getDriverClassName() {
        return driverClassName;
    }
    public void setDriverClassName(String driverClassName) {
        this.driverClassName = driverClassName;
    }
    public String getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "OpenDataSource [driverClassName=" + driverClassName + ", url=" + url + ", userName=" + userName
                + ", password=" + password + ", coreSize=" + coreSize + ", maxSize=" + maxSize + "]";
    }
    
}

package test;

import java.lang.reflect.Constructor;

import org.junit.Test;

public class TestReflect01 {
    @Test
    public void testObeject01() throws Exception{
        //1.获取类对象
        //2.获取构造方法对象
        //3.设置构造方法对象可访问
        //4.执行构造方法构建类的对象
        //5.输出对象信息
        String clsName="utils.OpenDataSource";
        //泛型中用?带表任意的一种类型
        //代表它是object类的子类
        //Class<? extends Object> c=Class.forName(clsName);
        //但是不能写
        //Class<Object> c=Class.forName(clsName);//不能直接写Object
        Class<?> c=Class.forName(clsName);
        Constructor<?> con = c.getDeclaredConstructor();
        con.setAccessible(true);
        //安全指的是不是直接访问，但是可以间接访问
        Object obj = con.newInstance();
        System.out.println(obj);
            
    }
}

OpenDataSource.OpenDataSource()-0
OpenDataSource [driverClassName=null, url=null, userName=null, password=null, coreSize=null, maxSize=null]

package test;

import java.lang.reflect.Constructor;

import org.junit.Test;

public class TestReflect01 {
    
    @Test
    public void testObeject02() throws Exception{
        //1.获取类对象
        //2.获取构造方法对象
        //3.设置构造方法对象可访问
        //4.执行构造方法构建类的对象
        //5.输出对象信息
        String clsName="utils.OpenDataSource";
        //泛型中用?带表任意的一种类型
        //代表它是object类的子类
        //Class<? extends Object> c=Class.forName(clsName);
        //但是不能写
        //Class<Object> c=Class.forName(clsName);//不能直接写Object
        Class<?> c=Class.forName(clsName);
        Constructor<?> con = c.getDeclaredConstructor(int.class,int.class);
        //修改访问修饰符
        con.setAccessible(true);
        //安全指的是不是直接访问，但是可以间接访问
        Object obj = con.newInstance(10,100);
        System.out.println(obj);
        
    }
}

OpenDataSource.OpenDataSource()-2
OpenDataSource [driverClassName=null, url=null, userName=null, password=null, coreSize=10, maxSize=100]

最后编辑于：2018.09.04 11:25:07