Java判断Map值的类型

你的名字 2023-06-11 07:23 49阅读 0赞

1、创建测试类（TestMap1.java）

package com.jeff;
    
    import java.util.HashMap;
    import java.util.Map;
    
    public class TestMap1 { 
    
    	public static void main(String[] args) { 
    		Map<String, Object> map = new HashMap<String, Object>();
    		map.put("str", "Jeff");
    		map.put("int", Integer.MAX_VALUE);
    		map.put("long", Long.MAX_VALUE);
    		map.put("float", Float.MAX_VALUE);
    		map.put("double", Double.MAX_VALUE);
    		map.put("u", new User("Jeff", "123456"));
    		map.forEach((key, value) -> { 
    			if (value instanceof String) { 
    				System.out.println("String类型-->" + key + ":" + value);
    			} else if (value instanceof Integer) { 
    				System.out.println("Integer类型-->" + key + ":" + value);
    			} else if (value instanceof Long) { 
    				System.out.println("Long类型-->" + key + ":" + value);
    			} else if (value instanceof Float) { 
    				System.out.println("Float类型-->" + key + ":" + value);
    			} else if (value instanceof Double) { 
    				System.out.println("Double类型-->" + key + ":" + value);
    			} else if (value instanceof User) { 
    				System.out.println("User类型-->" + key + ":" + value);
    			}
    		});
    	}
    
    }
    
    class User { 
    
    	private String userName;
    	private String password;
    
    	public User(String userName, String password) { 
    		super();
    		this.userName = userName;
    		this.password = password;
    	}
    
    	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 "User [userName=" + userName + ", password=" + password + "]";
    	}
    
    }

2、控制台输出结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]: /images/20230531/7431e6a6faf74f21b25477b571aa2903.png