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This article mainly shows you "how to use Java's launch mechanism to traverse the modified values of all fields", the content is simple and clear, and I hope it can help you solve your doubts. Let me lead you to study and learn "how to use Java's launch mechanism to traverse the modified values of all fields".

Java modifies values through reflection traversing all fields to avoid repeating set and get, such as a dozen fields in a table, while there are eight or nine picture storage fields in this table. When returning this entity class, you need to encrypt the picture or do other operations. After the query result of the entity class comes out, the get repair one by one, and then set assignment, a lot of code, in addition, if there are multiple interfaces to use There will be duplicate code. Through the reflection of java, traverse all the fields and make a judgment. The value taken is linked with the picture. The operation saves a lot of code. The code is posted below.

Import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import java.beans.PropertyDescriptor;import java.lang.reflect.Field;import java.lang.reflect.Method;public class ClassUtil {private final Logger logger = LoggerFactory.getLogger (getClass ()) / * by reflecting all fields, fields with pictures, reassign * * @ param obj object * / public void setImageValue (Object obj) {try {Class aClass = obj.getClass (); Field [] fields = aClass.getDeclaredFields () For (Field field: fields) {PropertyDescriptor pd = new PropertyDescriptor (field.getName (), aClass); / / get get method Method getMethod = pd.getReadMethod (); / / get set method Method setMethod = pd.getWriteMethod () / / get the value Object o = getMethod.invoke (obj) through the get method; if (o! = null) {String s = o.toString () If (s.contains ("jpg")) {/ / Business Operation / / Update to the new value setMethod.invoke (obj, builder.toString ()) } catch (Exception e) {e.printStackTrace ();} ps: let's look at several ways to traverse the Java array

Reference for array traversal method:

Method 1: for loop traversal

Public static void main (String [] args) {int Arr [] [] = {{1 int [j] +) {System.out.print (Arr [I] +) {System.out.print (Arr [j] + ");}

Method 2: foreach traversal

Int a [] = {1, System.out.println 2, 3, 4}; for (int element:a) {System.out.println (element);}

Method 3: toString (or deepToString) static method traversal in the Arrays utility class

Int a [] = {1pr 2je 3je 4}; int b [] = {{3jue 4}, {1jue 2}}; System.out.println (Arrays.toString (a)); System.out.println (Arrays.deepToString (b)); java basic data types what Java basic data types can be divided into: 1, integer types, used to represent integer data types. 2. Floating point type, which is used to represent the data type of decimals. 3. Character type. The keyword of character type is "char". 4. Boolean type, which is the basic data type that represents logical values.

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