tryfinally处理资源泄露隐患优化

使用java7的新api try(){};

普通做法

private String traditionalTryCatch() throws IOException {

        // 1. 单一资源的关闭
//        String line = null;
//        BufferedReader br = new BufferedReader(new FileReader(""));
//        try {
//            line = br.readLine();
//        } finally {
//            br.close();
//        }
//        return line;

        // 2. 多个资源的关闭
        // 第一个资源
        InputStream in = new FileInputStream("");
        try {
            // 第二个资源
            OutputStream out = new FileOutputStream("");
            try {
                byte[] buf = new byte[100];
                int n;

                while ((n = in.read(buf)) >= 0)
                    out.write(buf, 0, n);
            } finally {
                out.close();
            }
        } finally {
            in.close();
        }

        return null;
    }

新做法

private String newTryWithResources() throws IOException {

        // 1. 单个资源的使用与关闭
//        try (BufferedReader br = new BufferedReader(new FileReader(""))) {
//            return br.readLine();
//        }

        // 2. 多个资源的使用与关闭
        try (FileInputStream in = new FileInputStream("");
             FileOutputStream out = new FileOutputStream("")
        ) {
            byte[] buffer = new byte[100];
            int n = 0;
            while ((n = in.read(buffer)) != -1) {
                out.write(buffer, 0, n);
            }
        }
        return null;
    }