BeanUtils 使用

桃扇骨 2022-05-20 06:27 149阅读 0赞

### 文章目录 ###

*   *  代码
     *  代码运行情况
     *   *  运行环境
         *  问题
         *  截图
     *  说明
     *  最终代码
     *   *  截图

## 代码 ##

package cn.itcast.store.test;
    
    import java.lang.reflect.InvocationTargetException;
    import java.util.HashMap;
    import java.util.Map;
    
    import org.apache.commons.beanutils.BeanUtils;
    import org.junit.Test;
    
    import cn.itcast.store.domain.User;
    
    public class TestBeanUtils { 
    
    	@Test
    	public void Test02() { 
    		Map<String, String[]> map = new HashMap<String, String[]>();
    		map.put("username", new String[] { "LILei"});
    		map.put("password", new String[] { "123*LiLei"});
    		// A处代码
    		map.put("birthday", new String[] { "1997-03-15"});
    		
    		User user = new User();
    		try { 
    			BeanUtils.populate(user, map);
    			System.out.println(user);
    		} catch (IllegalAccessException e) { 
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (InvocationTargetException e) { 
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    }

## 代码运行情况 ##

### 运行环境 ###

**Eclipse， jdk10， tomcat8.0.5， JUnit4**

### 问题 ###

A 处代码日期格式为字符串，但是 `User` 中的代码 **日期** 是 `Date` 类型，转换出现问题。正如通过 `IntegerConverter` 转换器将 `String` 类型，转换为 `int` 类型。 `BeanUtils` 需要一个转换器

### 截图 ###

![这里写图片描述][70]

## 说明 ##

日期装换说明：

*  BeanUtils进行设置属性时，对于String,int可以自动转换。如**User** 中的 **uid**，**username**， **password** 等等。
 *  其他对象类型，需要一个转换器
 *  end

## 最终代码 ##

### 截图 ###

![这里写图片描述][70 1]

package cn.itcast.store.test;
    
    import java.lang.reflect.InvocationTargetException;
    import java.util.HashMap;
    import java.util.Map;
    
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    import org.apache.commons.beanutils.BeanUtils;
    import org.apache.commons.beanutils.ConvertUtils;
    import org.apache.commons.beanutils.Converter;
    import org.junit.Test;
    
    import cn.itcast.store.domain.User;
    
    public class TestBeanUtils { 
    
    	@Test
    	public void Test02() { 
    		Map<String, String[]> map = new HashMap<String, String[]>();
    		map.put("username", new String[] {  "hujinn" });
    		map.put("password", new String[] {  "123*hujin" });
    		map.put("birthday", new String[] {  "1997-03-15" });
    
    		User user = new User();
    		try { 
    			ConvertUtils.register(new Converter() { 
    
    				public Object convert(Class type, Object value) { 
    
    					SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
    					try { 
    						return simpleDateFormat.parse(value.toString());
    					} catch (ParseException e) { 
    						// TODO Auto-generated catch block
    						e.printStackTrace();
    					}
    					return null;
    				}
    			}, Date.class);
    			BeanUtils.populate(user, map);
    			System.out.println(user);
    		} catch (IllegalAccessException e) { 
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (InvocationTargetException e) { 
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    }

User 对象

package cn.itcast.store.domain;
    
    import java.util.Date;
    
    // 无参数的构造器
    // private成员
    // public get/set
    
    public class User {
    	private String uid;
    	private String username;
    	private String password;
    	private String name;
    	private String email;
    	private String telephone;
    	private Date birthday;
    	private String sex;
    	private int state; 
    	private String code; 
    	public String getUid() {
    		return uid;
    	}
    	public void setUid(String uid) {
    		this.uid = uid;
    	}
    	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;
    	}
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public String getEmail() {
    		return email;
    	}
    	public void setEmail(String email) {
    		this.email = email;
    	}
    	public String getTelephone() {
    		return telephone;
    	}
    	public void setTelephone(String telephone) {
    		this.telephone = telephone;
    	}
    	public Date getBirthday() {
    		return birthday;
    	}
    	public void setBirthday(Date birthday) {
    		this.birthday = birthday;
    	}
    	public String getSex() {
    		return sex;
    	}
    	public void setSex(String sex) {
    		this.sex = sex;
    	}
    	public int getState() {
    		return state;
    	}
    	public void setState(int state) {
    		this.state = state;
    	}
    	public String getCode() {
    		return code;
    	}
    	public void setCode(String code) {
    		this.code = code;
    	}
    	public User() {
    		// TODO Auto-generated constructor stub
    	}
    	public User(String uid, String username, String password, String name, String email, String telephone,
    			Date birthday, String sex, int state, String code) {
    		super();
    		this.uid = uid;
    		this.username = username;
    		this.password = password;
    		this.name = name;
    		this.email = email;
    		this.telephone = telephone;
    		this.birthday = birthday;
    		this.sex = sex;
    		this.state = state;
    		this.code = code;
    	}
    	@Override
    	public String toString() {
    		return "User [uid=" + uid + ", username=" + username + ", password=" + password + ", name=" + name + ", email="
    				+ email + ", telephone=" + telephone + ", birthday=" + birthday + ", sex=" + sex + ", state=" + state
    				+ ", code=" + code + "]";
    	}
    	
    
    }

代码  
方法一

class MyDateConverter implements Converter { 
    
        @Override
        // 需要 将value数据转换 c的类型
        // value 是 String类型，将String转换Date类型
        public Object convert(Class c, Object value) { 
            String s = (String) value; // 代表用户输入生日
            //定义格式
            DateFormat dateFormat = new SimpleDateFormat("yyyy年MM月dd日");
            try { 
                Object result = dateFormat.parse(s); // 将String解析为 Date，将日期变为字符串使用format方法
                return result;
            } catch (ParseException e) { 
                e.printStackTrace();
            }
            return null;
        }
    }
    
    // 自定义转换
    // 将String类型 转换 java.util.Date类型 
    // 在封装数据之前 ，注册转换
    ConvertUtils.register(new MyDateConverter(), Date.class);

方法二

ConvertUtils.register(new Converter() { 
    
    				public Object convert(Class type, Object value) { 
    
    					SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
    					try { 
    						return simpleDateFormat.parse(value.toString());
    					} catch (ParseException e) { 
    						// TODO Auto-generated catch block
    						e.printStackTrace();
    					}
    					return null;
    				}
    			}, Date.class);

[70]: /images/20220520/457854b9427947c98337cf92ef079bec.png
[70 1]: /images/20220520/04681eb80e12466e81e4fd78972e61cf.png