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This article mainly explains "how to use Spring SpEL", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's learn how to use Spring SpEL!

SpEL Spring expression language, in front of thousands of people, is very useful when matching different data according to different attributes of different users. The following simple examples show how to use it.

import com.google.common.collect.Lists;import com.google.common.collect.Sets;import org.springframework.expression.Expression;import org.springframework.expression.ExpressionParser;import org.springframework.expression.spel.standard.SpelExpressionParser;import org.springframework.expression.spel.support.StandardEvaluationContext;import java.util.List;import java.util.Set;public class Test1 { //User tag list private List userTagList; //List of user mobile phone numbers private List userMobileList; public void setUserTagList(List userTagList) { this.userTagList = userTagList; } public void setUserMobileList(List userMobileList) { this.userMobileList = userMobileList; } /** * all match * Target attributes are all in user attributes, return true * * @param targetTags Target Properties * @return */ public boolean tagMatchAll(Integer... targetTags) { //User tag list Set userSet = Sets.newHashSet(userTagList); //Target Properties Set targetSet = Sets.newHashSet(targetTags); //copy target attribute, original attribute value cannot be changed Set targetSetCopy = Sets.newHashSet(targetSet); targetSetCopy.removeAll(userSet); return targetSetCopy.isEmpty(); } /** * all match * * @param targetMobiles * @return */ public boolean mobileMatchAll(String... targetMobiles) { //User tag list Set userSet = Sets.newHashSet(userMobileList); //Target Properties Set targetSet = Sets.newHashSet(targetMobiles); //copy target attribute, original attribute value cannot be changed Set targetSetCopy = Sets.newHashSet(targetSet); targetSetCopy.retainAll(userSet); return ! targetSetCopy.isEmpty(); } /** * Match to one (intersection is not empty) Returns true * * @param targetTags * @return */ public boolean tagMatchAny(Integer... targetTags) { //User tag list Set userTagSet = Sets.newHashSet(userTagList); //Target Properties Set targetSet = Sets.newHashSet(targetTags); //copy target attribute, original attribute value cannot be changed Set targetSetCopy = Sets.newHashSet(targetSet); targetSetCopy.retainAll(userTagSet); return ! targetSetCopy.isEmpty(); } /** * None matched (intersection is empty) Returns true * * @param targetTags * @return */ public boolean tagMatchNotAny(Integer... targetTags) { return ! this.tagMatchAny(targetTags); } public static void test() { List userTagList = Lists.newArrayList(10, 20, 30); List userMobileList = Lists.newArrayList("188"); Test1 scene = new Test1(); scene.setUserTagList(userTagList); scene.setUserMobileList(userMobileList); StandardEvaluationContext context = new StandardEvaluationContext(); context.setVariable("scene", scene); ExpressionParser parser = new SpelExpressionParser(); //All matches String sceneCondition1 = "#scene.tagMatchAll(10, 20) && #scene.mobileMatchAll('188')"; Expression expression1 = parser.parse_Expression(sceneCondition1); Boolean isTagMatchAll1 = expression1.getValue(context, Boolean.class); System.out.println("MatchAll 1:" + isTagMatchAll1); // true String sceneCondition2 = "#scene.tagMatchAll(10, 20, 21)"; Expression expression2 = parser.parse_Expression(sceneCondition2); Boolean isTagMatchAll2 = expression2.getValue(context, Boolean.class); System.out.println("All Match 2:" + isTagMatchAll2); // false:userTagList does not contain 21 //match any one String sceneCondition3 = "#scene.tagMatchAny(10, 21, 31)"; Expression expression3 = parser.parse_Expression(sceneCondition3); Boolean isTagMatchAny3 = expression3.getValue(context, Boolean.class); System.out.println("Match any: " + isTagMatchAny3); // true matches to 10 //completely mismatched String sceneCondition4 = "#scene.tagMatchNotAny(11, 21, 31)"; Expression expression4 = parser.parse_Expression(sceneCondition4); Boolean isTagMatchNotAny4 = expression4.getValue(context, Boolean.class); System.out.println("Total Mismatch: " + isTagMatchNotAny4); // true matches to 10 } public static void main(String[] args) { test(); }} At this point, I believe that everyone has a deeper understanding of "how to use Spring SpEL", so you may wish to actually operate it! Here is the website, more related content can enter the relevant channels for inquiry, pay attention to us, continue to learn!

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