在mybatis中的xml写sql的时候如果查询的条件非常多就会多出很多行的代码
这里介绍一下我的想法，最近想到的，实践了一下是可行的，和xml的if拼接是一样的
使用javapot实现动态拼接代码
- 读取文件
public static String root = "com.finish.mp.";
public static String boPackage = "t1.bo";
public static String enumPath = "com.finish.mp.sysenum";
@Test
public void autoQueryPage() throws Exception {
File file = new File(T2.class.getResource("/").getPath());
String parent = new File(file.getParent()).getParent();
String rootPath = parent + "\\src\\main\\java\\" + root.replace(".", "\\");
File[] fileBO = new File(rootPath + boPackage.replace(".", "\\")).listFiles();
TypeSpec.Builder classSpec = TypeSpec.classBuilder("Page2Sql")
.addModifiers(Modifier.PUBLIC);
List<String> collect = Arrays.stream(fileBO).map(file1 -> file1.getName().split("\\.")[0]).collect(Collectors.toList());
for (String s : collect) {
Class<?> bo = Class.forName(root + boPackage + "." + s);
MethodSpec bo2sql = createMethod(bo);
classSpec.addMethod(bo2sql);
}
TypeSpec build = classSpec.build();
File file1 = new File(rootPath + "\\utils");
if (!file1.exists()) {
file1.mkdirs();
}
JavaFile.builder("", build).build().writeTo(file1);
}
-
编写注解 划线的不是这个里面的
image.png -
在指定的字段使用注解
image.png - 编写生成方法的javapot代码 这里的dr是逻辑删除
private MethodSpec createMethod(Class<?> bo) throws Exception {
String boName = toLowerCaseFirstOne(bo.getSimpleName());
StringBuilder s = new StringBuilder(boName);
boName = s.delete(s.length() - 2, s.length()).toString();
MethodSpec.Builder builder = MethodSpec.methodBuilder(toLowerCaseFirstOne(boName) + "2Sql")
.addParameter(ParameterSpec.builder(bo, boName).build())
.returns(String.class)
.addModifiers(Modifier.PUBLIC, Modifier.STATIC);
builder.addStatement("StringBuilder st = new StringBuilder()");
builder.addStatement("st.append(\"where t.dr = 0\")");
Field[] fields1 = bo.getSuperclass().getDeclaredFields();
Field[] fields2 = bo.getDeclaredFields();
List<Field> fields = new ArrayList<>();
fields.addAll(Arrays.asList(fields1));
fields.addAll(Arrays.asList(fields2));
for (Field field : fields) {
field.setAccessible(true);
TableField annotation = field.getAnnotation(TableField.class);
Like like = field.getAnnotation(Like.class);
LeftLike leftLike = field.getAnnotation(LeftLike.class);
RightLike rightLike = field.getAnnotation(RightLike.class);
//这里注解名字改了，就是大于小于和开闭区间的意思
LessThan endTime = field.getAnnotation(LessThan.class);
GreaterThan startTime = field.getAnnotation(GreaterThan.class);
SqlIgnore sqlIgnore = field.getAnnotation(SqlIgnore.class);
if (sqlIgnore != null) {
continue;
}
String name = field.getName();
if (annotation != null) {
name = annotation.value();
}
String s1 = boName + ".get" + toUpperCaseFirstOne(field.getName());
if (!field.getType().getName().contains(enumPath)) {
if (field.getType() == String.class) {
builder.addCode("if(" + s1 + "()!=null&&! \"\".equals(" + s1 + "())){");
if (like != null) {
builder.addStatement("st.append(\" and t." + name + " = \").append(\"'%\").append(" + s1 + "()).append(\"%'\")");
} else if (leftLike != null) {
builder.addStatement("st.append(\" and t." + name + " = \").append(\"'%\").append(" + s1 + "()).append(\"'\")");
} else if (rightLike != null) {
builder.addStatement("st.append(\" and t." + name + " = \").append(\"'\").append(" + s1 + "()).append(\"%'\")");
} else if (endTime != null) {
if (endTime.value() == 1) {
builder.addStatement("st.append(\" and t." + name + " < \").append(\"'\").append(" + s1 + "()).append(\"'\")");
} else {
builder.addStatement("st.append(\" and t." + name + " <= \").append(\"'\").append(" + s1 + "()).append(\"'\")");
}
} else if (startTime != null) {
if (startTime.value() == 1) {
builder.addStatement("st.append(\" and t." + name + " > \").append(\"'\").append(" + s1 + "()).append(\"'\")");
} else {
builder.addStatement("st.append(\" and t." + name + " >= \").append(\"'\").append(" + s1 + "()).append(\"'\")");
}
} else {
builder.addStatement("st.append(\" and t." + name + " = \").append(\"'\").append(" + s1 + "()).append(\"'\")");
}/* else {
builder.addStatement("st.append(\" and t." + name + " = \").append(\"'\").append(" + s1 + "()).append(\"%'\")");
}*/
} else if (field.getType().getName().contains("java")) {
builder.addCode("if(" + s1 + "()!=null){");
builder.addStatement("st.append(\" and t." + name + " = \").append(" + s1 + "())");
}
} else {
builder.addCode("if(" + s1 + "()!=null){");
builder.addStatement("st.append(\" and t." + name + " = \").append(" + s1 + "().getIndex())");
}
builder.addCode("}");
}
builder.addStatement("return st.toString()");
return builder.build();
}
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生成样例 这里没有加上包 手动加下
image.png -
代码实践
image.png
