利用commons-beanutils.jar将对象为空的属性设置为null

Bertha 。 2021-10-13 01:23 480阅读 0赞

### 利用commons-beanutils.jar将对象为空的属性设置为null ###

*  代码
 *   *   *  pom.xml
         *  Student.java
         *  Student1.java
         *  ObjectExample.java
         *  ObjectExampleTest.java
 *  运行

# 代码 #

### pom.xml ###

<dependencies>
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
            
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.20</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-simple</artifactId>
                <version>1.7.25</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.35</version>
            </dependency>
    
            
            <dependency>
                <groupId>commons-beanutils</groupId>
                <artifactId>commons-beanutils</artifactId>
                <version>1.9.3</version>
            </dependency>
    
        </dependencies>

### Student.java ###

package com.ydfind.object.model;
    
    import lombok.Data;
    
    @Data
    public class Student {
    
        private Integer id;
    
        private Integer age;
    
        private String name;
    
        private String address;
    
        private String phone;
    
        private String sex;
    
        public Student(){
    
        }
    
        public Student(Integer id, Integer age, String name, String address, String phone, String sex){
            this.id = id;
            this.name = name;
            this.age = age;
            this.address = address;
            this.phone = phone;
            this.sex = sex;
        }
    }

### Student1.java ###

package com.ydfind.object.model;
    
    public class Student1 {
    
        private Integer id;
    
        private Integer age;
    
        private String name;
    
        private String address;
    
        private String phone;
    
        private String sex;
    
        public Student1(){
    
        }
    
        public Student1(Integer id, Integer age, String name, String address, String phone, String sex){
            this.id = id;
            this.name = name;
            this.age = age;
            this.address = address;
            this.phone = phone;
            this.sex = sex;
        }
    
        public void setName(String name){
            this.name = name;
        }
    
        public String getName(){
            return this.name;
        }
    
        public void setAddress(String address){
            this.address = address;
        }
    
        public void getPhone(String phone){
            this.phone = phone;
        }
    }

### ObjectExample.java ###

package com.ydfind.object;
    
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.beanutils.PropertyUtils;
    
    import java.lang.reflect.Field;
    import java.lang.reflect.InvocationTargetException;
    import java.lang.reflect.Type;
    
    @Slf4j
    public class ObjectExample {
    
        /**
         * 对象中字符串属性，若为空则设置为null
         * @param obj
         * @throws IllegalAccessException
         * @throws NoSuchMethodException
         * @throws InvocationTargetException
         */
        public static void changeStringToNull(Object obj) throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
            for (Class<?> clazz = obj.getClass(); clazz != Object.class; clazz = clazz.getSuperclass()) {
    
                Field fields[] = clazz.getDeclaredFields();
    
                // 遍历属性值，取得所有属性为 null 值的
                for (Field field : fields) {
                    Type t = field.getGenericType();
                    if (t.getTypeName().equals(String.class.getTypeName())) {
                        Object property = PropertyUtils.getProperty(obj, field.getName());
                        if (property != null && "".equals(String.valueOf(property).trim())) {
                            log.info("将设置{}为null", field.getName());
                            PropertyUtils.setProperty(obj, field.getName(), null);
                        }
                    }
                }
            }
        }
    
    }

### ObjectExampleTest.java ###

package com.ydfind.object;
    
    import com.ydfind.object.model.Student;
    import com.ydfind.object.model.Student1;
    import org.junit.Test;
    
    import java.lang.reflect.InvocationTargetException;
    
    public class ObjectExampleTest {
    
        @Test
        public void testChangeStringToNull() throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
            // public Student(Integer id, Integer age, String name, String address, String phone, String sex)
            Student student = new Student(1, 18, "张三", "", " ", "男");
            System.out.println("student define: " + student);
            ObjectExample.changeStringToNull(student);
            System.out.println("student process: " + student);
            Student1 student1 = new Student1(1, 18, " ", "", " ", "男");
            System.out.println("student1 define: " + student1);
            ObjectExample.changeStringToNull(student1);
            System.out.println("student1 process: " + student1);
    
        }
    }

# 运行 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NuZGF5WVU_size_16_color_FFFFFF_t_70]  
可以看到Student对象可以正常运行，但address属性因为没有get方法，导致PropertyUtils.getProperty报错；

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