Java Class New Instance newInstance(String klass)

Description

new Instance

License

Apache License

Declaration

public static Object newInstance(String klass) 

Method Source Code

//package com.java2s;
/**//from w w  w .j av a2  s  . co  m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.reflect.Constructor;

public class Main {
    public static Object newInstance(String klass) {
        try {
            Class c = Class.forName(klass);
            return c.newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static Object newInstance(String klass, Object... params) {
        try {
            Class c = Class.forName(klass);
            Constructor[] constructors = c.getConstructors();
            boolean found = false;
            Constructor con = null;
            for (Constructor cons : constructors) {
                if (cons.getParameterTypes().length == params.length) {
                    con = cons;
                    break;
                }
            }

            if (con == null) {
                throw new RuntimeException(
                        "Cound not found the corresponding constructor, params=" + params.toString());
            } else {
                if (con.getParameterTypes().length == 0) {
                    return c.newInstance();
                } else {
                    return con.newInstance(params);
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

Related

1. newInstance(String className, Object[] args)
2. newInstance(String classname, Properties properties)
3. newInstance(String clazz)
4. newInstance(String clazzStr)
5. newInstance(String cls, Class interfaceType)
6. newInstance(String name)
7. newInstance(String name, ClassLoader loader)
8. newInstance(String s)
9. newInstance(String type)