Mybatis生成器插件扩展，生成findInSet方法

梦里梦外; 2022-12-26 14:27 173阅读 0赞

public Criteria andNameFindInSet(String value) {
                addCriterionPattern("find_in_set($value, `name`)", value, "name");
                return (Criteria) this;
            }
    
            public Criteria andNamePattern(String pattern, String value) {
                addCriterionPattern(pattern.replace("##column##", "`name`"), value, "name");
                return (Criteria) this;
            }

### 一、生成模式原理 ###

（1）Example.Criterion添加pattern字段

public static class Criterion {
            private String condition;
    
            private Object value;
    
            private Object secondValue;
    
            private boolean noValue;
    
            private boolean singleValue;
    
            private boolean betweenValue;
    
            private boolean listValue;
    
            private String typeHandler;
    
            private boolean pattern;
    }

（2）Example.GeneratedCriteria加方法addCriterionPattern

protected abstract static class GeneratedCriteria
    
           protected void addCriterionPattern(String condition, Object value, String property) {
                if (value == null) {
                    throw new RuntimeException("Value for " + property + " cannot be null");
                }
                Criterion c = new Criterion(condition, value);
                c.setPattern(true);
                criteria.add(c);
            }
    }

（3） 加对应列FindInSet方法

protected abstract static class GeneratedCriteria {
    
            public Criteria andXXXFindInSet(String value) {
                addCriterionPattern("find_in_set(##value##, `xxx`)", value, "xxx");
                return (Criteria) this;
            }
    }

（4）改造XXXSqlProvider.applyWhere的 if (criterion.isNoValue()) 前增加模式代码

if (criterion.isPattern()) {
    	String value;
    	 if (criterion.getTypeHandler() == null) {
    		value = String.format(parmPhrase1, "", i, j).trim();
    	} else {
    		value = String.format(parmPhrase1_th, "", i, j, criterion.getTypeHandler()).trim();
    	}
    	sb.append(criterion.getCondition().replaceAll("##value##", value));
    } else if (criterion.isNoValue()) {
    	sb.append(criterion.getCondition());
    } else if (criterion.isSingleValue()) {
    
    }

（5）改造XXXMapper.xml的<when test="criterion.noValue">前增加模式代码

<when test="criterion.pattern">
      and
      <foreach collection="criterion.condition.split('##value##')" item="criterionCond" separator="#{criterion.value}">
    	${criterionCond}
      </foreach>
    </when>
    <when test="criterion.noValue">
      and ${criterion.condition}
    </when>

### 二、插件代码 ###

package com.mk.mybatisgenerator.plugins;
    
    import org.mybatis.generator.api.IntrospectedColumn;
    import org.mybatis.generator.api.IntrospectedTable;
    import org.mybatis.generator.api.PluginAdapter;
    import org.mybatis.generator.api.dom.java.*;
    import org.mybatis.generator.api.dom.xml.Attribute;
    import org.mybatis.generator.api.dom.xml.Element;
    import org.mybatis.generator.api.dom.xml.TextElement;
    import org.mybatis.generator.api.dom.xml.XmlElement;
    import org.mybatis.generator.codegen.ibatis2.Ibatis2FormattingUtilities;
    import java.util.ArrayList;
    import java.util.List;
    
    public class MySQLMethodPlugin extends PluginAdapter {
    
        private final String valueName = "##value##";//值占位符
        private final String columnName = "##column##";//列名占位符
    
        public MySQLMethodPlugin() {
            super();
        }
    
        @Override
        public boolean validate(List<String> warnings) {
            return true;
        }
    
    
        /**
         * 重写example
         * @param topLevelClass
         * @param introspectedTable
         * @return
         */
        @Override
        public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
                                                  IntrospectedTable introspectedTable) {
    
            addCriterionPattern(topLevelClass, introspectedTable);//增加模式匹配
            addFindInSet(topLevelClass, introspectedTable);//增加find_in_set方法
            addPattern(topLevelClass,  introspectedTable);//增加模式方法
    
            return true;
        }
    
    
        /**
         * xml ExampleWhere重写
         * @param element
         * @param introspectedTable
         * @return
         */
        @Override
        public boolean sqlMapExampleWhereClauseElementGenerated(XmlElement element, IntrospectedTable introspectedTable) {
    
    
            XmlElement whereElement = (XmlElement) element.getElements().get(0);
            XmlElement foreachElement = (XmlElement) whereElement.getElements().get(0);
            XmlElement ifElement = (XmlElement) foreachElement.getElements().get(0);
            XmlElement trimElement = (XmlElement) ifElement.getElements().get(0);
            XmlElement foreachCriteriaElement = (XmlElement) trimElement.getElements().get(0);
            XmlElement chooseElement = (XmlElement) foreachCriteriaElement.getElements().get(0);
    
            for (Element ele : chooseElement.getElements()) {
                XmlElement noValueElement = (XmlElement) ele;
                for (Attribute attribute : noValueElement.getAttributes()) {
                    //找到criterion.noValue行插入模式代码
                    if (attribute.getName().equals("test") && attribute.getValue().equals("criterion.noValue")) {
    
                        XmlElement patternElement = new XmlElement("when");
                        patternElement.addAttribute(new Attribute("test", "criterion.pattern"));
                        //<foreach collection="oredCriteria" item="criteria" separator="or">
                        XmlElement forElement = new XmlElement("foreach");
                        forElement.addAttribute(new Attribute("collection", "criterion.condition.split('" + valueName + "')"));
                        forElement.addAttribute(new Attribute("item", "criterionCond"));
                        forElement.addAttribute(new Attribute("separator", "#{criterion.value}"));
                        forElement.addElement(new TextElement("${criterionCond}"));
    
                        patternElement.addElement(new TextElement("and"));
                        patternElement.addElement(forElement);
                        chooseElement.addElement(0, patternElement);
                        return true;
                    }
                }
            }
    
    
            throw new RuntimeException("ChooseElement not exist");
        }
    
        /**
         * 重写ApplyWhere方法
         * @param method
         * @param topLevelClass
         * @param introspectedTable
         * @return
         */
        @Override
        public boolean providerApplyWhereMethodGenerated(Method method, TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    
            List<String> lines = method.getBodyLines();
            for (int i = 0, len = lines.size(); i < len; i++) {
                String line = lines.get(i).trim();
                //找到criterion.noValue行插入模式代码
                if (line.matches("if\\s*\$criterion\\.isNoValue\\(\$\\)\\s*\\{")) {
                    lines.remove(i);
                    List<String> appends = new ArrayList<>();
                    appends.add("if (criterion.isPattern()) {");
                    appends.add("String value;");
                    appends.add(" if (criterion.getTypeHandler() == null) {");
                    appends.add("value = String.format(parmPhrase1, \"\", i, j).trim();");
                    appends.add("} else {");
                    appends.add("value = String.format(parmPhrase1_th, \"\", i, j, criterion.getTypeHandler()).trim();");
                    appends.add("}");
                    appends.add("sb.append(criterion.getCondition().replaceAll(\"" + valueName + "\", value));");
                    appends.add("} else " + line);
                    method.addBodyLines(i, appends);
                    return true;
                }
            }
            throw new RuntimeException("criterion.isNoValue() not exist");
        }
    
        /*
             protected void addCriterionPattern(String condition, Object value, String property) {
                    if (value == null) {
                        throw new RuntimeException("Value for " + property + " cannot be null");
                    }
                    Criterion c = new Criterion(condition, value);
                    c.setPattern(true);
                    criteria.add(c);
                }
             */
        public void addCriterionPattern(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
    
            addCriterionPatternField(topLevelClass, introspectedTable);
    
            InnerClass criteria = null;
            // first, find the Criteria inner class
            for (InnerClass innerClass : topLevelClass.getInnerClasses()) {
                if ("GeneratedCriteria".equals(innerClass.getType().getShortName())) { //$NON-NLS-1$
                    criteria = innerClass;
                    break;
                }
            }
            if (criteria == null) {
                throw new RuntimeException("GeneratedCriteria not exist");
            }
    
            Method method = new Method();
            method.setVisibility(JavaVisibility.PROTECTED);
            method.addParameter(new Parameter(FullyQualifiedJavaType.getStringInstance(), "condition"));
            method.addParameter(new Parameter(FullyQualifiedJavaType.getObjectInstance(), "value"));
            method.addParameter(new Parameter(FullyQualifiedJavaType.getStringInstance(), "property"));
    
            method.setName("addCriterionPattern");
    
            method.addBodyLine("if (value == null) {");
            method.addBodyLine("throw new RuntimeException(\"Value for \" + property + \" cannot be null\");");
            method.addBodyLine("}");
            method.addBodyLine("Criterion c = new Criterion(condition, value);");
            method.addBodyLine("c.setPattern(true);");
            method.addBodyLine("criteria.add(c);");
            criteria.addMethod(method);
    
        }
    
        public void addCriterionPatternField(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
            InnerClass criterion = null;
            // first, find the Criteria inner class
            for (InnerClass innerClass : topLevelClass.getInnerClasses()) {
                if ("Criterion".equals(innerClass.getType().getShortName())) { //$NON-NLS-1$
                    criterion = innerClass;
                    break;
                }
            }
            if (criterion == null) {
                throw new RuntimeException("Criterion not exist");
            }
    
            FullyQualifiedJavaType booleanPrimitive = FullyQualifiedJavaType.getBooleanPrimitiveInstance();
    
            Field pattern = new Field();
            pattern.setName("pattern");
            pattern.setVisibility(JavaVisibility.PRIVATE);
            pattern.setType(booleanPrimitive);
            criterion.addField(pattern);
    
            Method setPattern = new Method();
            setPattern.setVisibility(JavaVisibility.PUBLIC);
            setPattern.setName("setPattern");
            setPattern.addParameter(new Parameter(booleanPrimitive, "pattern"));
            setPattern.addBodyLine("this.pattern = pattern;");
            criterion.addMethod(setPattern);
    
            Method isPattern = new Method();
            isPattern.setVisibility(JavaVisibility.PUBLIC);
            isPattern.setReturnType(booleanPrimitive);
            isPattern.setName("isPattern");
            isPattern.addBodyLine("return pattern;");
            criterion.addMethod(isPattern);
        }
    
        public void addFindInSet(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
            addFindInSetPattern(topLevelClass, introspectedTable, "findInSet", "find_in_set(" + valueName + ", " + columnName + ")");
        }
    
    
    
        public void addFindInSetPattern(TopLevelClass topLevelClass, IntrospectedTable introspectedTable, String opName, String pattern) {
            InnerClass criteria = null;
            // first, find the Criteria inner class
            for (InnerClass innerClass : topLevelClass.getInnerClasses()) {
                if ("GeneratedCriteria".equals(innerClass.getType().getShortName())) { //$NON-NLS-1$
                    criteria = innerClass;
                    break;
                }
            }
    
            if (criteria == null) {
                throw new RuntimeException("GeneratedCriteria not exist");
            }
    
            for (IntrospectedColumn introspectedColumn : introspectedTable
                    .getNonBLOBColumns()) {
                if (!introspectedColumn.isJdbcCharacterColumn()
                        || !introspectedColumn.isStringColumn()) {
                    continue;
                }
    
                Method method = new Method();
                method.setVisibility(JavaVisibility.PUBLIC);
                method.addParameter(new Parameter(introspectedColumn
                        .getFullyQualifiedJavaType(), "value")); //$NON-NLS-1$
    
                StringBuilder opNameBuilder = new StringBuilder(opName);
                opNameBuilder.setCharAt(0, Character.toUpperCase(opNameBuilder.charAt(0)));
                opName = opNameBuilder.toString();
    
                StringBuilder sb = new StringBuilder();
                sb.append(introspectedColumn.getJavaProperty());
                sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
                sb.insert(0, "and"); //$NON-NLS-1$
                sb.append(opName);
                method.setName(sb.toString());
                method.setReturnType(FullyQualifiedJavaType.getCriteriaInstance());
    
                sb.setLength(0);
                sb.append("addCriterionPattern(\"")
                        .append(pattern.replaceAll(columnName, Ibatis2FormattingUtilities.getAliasedActualColumnName(introspectedColumn)))
                        .append("\", value, \"")
                        .append(introspectedColumn.getJavaProperty());
                sb.append("\");");
                method.addBodyLine(sb.toString());
                method.addBodyLine("return (Criteria) this;");
    
                criteria.addMethod(method);
            }
        }
    
        public void addPattern(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
            addPatternMethod(topLevelClass, introspectedTable, "pattern");
        }
    
        public void addPatternMethod(TopLevelClass topLevelClass, IntrospectedTable introspectedTable, String opName){
            InnerClass criteria = null;
            // first, find the Criteria inner class
            for (InnerClass innerClass : topLevelClass.getInnerClasses()) {
                if ("GeneratedCriteria".equals(innerClass.getType().getShortName())) { //$NON-NLS-1$
                    criteria = innerClass;
                    break;
                }
            }
    
            if (criteria == null) {
                throw new RuntimeException("GeneratedCriteria not exist");
            }
    
            for (IntrospectedColumn introspectedColumn : introspectedTable
                    .getNonBLOBColumns()) {
                if (!introspectedColumn.isJdbcCharacterColumn()
                        || !introspectedColumn.isStringColumn()) {
                    continue;
                }
    
                Method method = new Method();
                method.setVisibility(JavaVisibility.PUBLIC);
                method.addParameter(new Parameter(FullyQualifiedJavaType.getStringInstance(), "pattern"));
                method.addParameter(new Parameter(introspectedColumn
                        .getFullyQualifiedJavaType(), "value"));
    
                StringBuilder opNameBuilder = new StringBuilder(opName);
                opNameBuilder.setCharAt(0, Character.toUpperCase(opNameBuilder.charAt(0)));
                opName = opNameBuilder.toString();
    
                StringBuilder sb = new StringBuilder();
                sb.append(introspectedColumn.getJavaProperty());
                sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
                sb.insert(0, "and"); //$NON-NLS-1$
                sb.append(opName);
                method.setName(sb.toString());
                method.setReturnType(FullyQualifiedJavaType.getCriteriaInstance());
    
                sb.setLength(0);
                sb.append("addCriterionPattern(pattern.replaceAll(\"")
                        .append(columnName).append("\", \"")
                        .append(Ibatis2FormattingUtilities.getAliasedActualColumnName(introspectedColumn)).append("\")")
                        .append(", value, \"")
                        .append(introspectedColumn.getJavaProperty());
                sb.append("\");");
                method.addBodyLine(sb.toString());
                method.addBodyLine("return (Criteria) this;");
    
                criteria.addMethod(method);
            }
        }
    
    }

### 三、配置插件 ###