java编译、执行、反编译

﹏ヽ暗。殇╰゛Y 2023-01-17 04:58 170阅读 0赞

### **一.JDK常用的几个工具** ###

1.  **javac 编译器**
2.  **java Java的语言解释器**
3.  **javap 类文件反汇编器**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70][]

**注意**：java 执行的时候，后面的调用类是写类的全路径，不是类所在的物理路径。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 1][]

**附javac 用法**

用法：javac <选项> <源文件>

其中，可能的选项包括：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 2][]

**注意：-cp**和-classpath，没区别，classpath参数太长了，所以提供cp作为缩写形式

## ##

### **二.  编译多文件** ###

**1.一次性编译所有.java文件**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 4][]

**2.编译指定的多个java文件**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 5][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 6][]

### **三. 引入外部jar包编译运行，**就用到了`-cp`命令。 ###

1.测试目录结构

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 7][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 8][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 9][]

import com.alibaba.fastjson.JSON;
    
    public class MathTest {
    	public int P(int a,int b) {
    		int c = a+b;
    		return c;
    	}
    	public static void main(String[] args) {
    		System.out.println(JSON.toJSONString("starting JSON..."));
    		System.out.println("starting......");
    	}
    }

** 开始编译**

![20210605225850420.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 10][]

**成功运行**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 11][]

**附java 用法**

用法：java <选项> <源文件>

其中，可能的选项包括：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 12][]

**注意：**

1.  javac -cp 指明了.java文件里import的类的位置
2.  java -cp 指明了执行这个class文件所需要的所有类的包路径-即系统类加载器的路径（涉及到类加载机制）  
    注意：路径在linux中用：隔开，在windows中用；隔开。对于.class文件来说，只需要指明包的路径即可；但是对于jar文件来说，必须要指定全路径即路径+文件名的格式，不能只指定一个路径

2.如果有多个第三方jar包，多个jar包的话windows使用`;`分隔，linux使用`:`分隔。  
如果相同路径有多个jar包的话可以使用通配符一起引入既`D:\java_work\jdbc\*.jar`

如：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 13][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 14][]

import com.alibaba.fastjson.JSON;
    import com.google.gson.Gson;
    
    public class A {
    	public int P(int a,int b) {
    		int c = a+b;
    		return c;
    	}
    	public static void main(String[] args) {
    		Gson gson = new Gson();
    		System.out.println(gson.toJson("starting gson..."));
    		System.out.println(JSON.toJSONString("starting JSON..."));
    		System.out.println("starting......");
    	}
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lpZ3VhbmdfODIw_size_16_color_FFFFFF_t_70 15][]

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[20210605225850420.png]: /images/20221022/5505fe668ee44c1f9238a7362b584161.png
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